Stimulus sequencer for a closed loop neuromodulator

ABSTRACT

This document discusses, among other things, a system and method for generating a sleep therapy stimulus waveform for a patient. Stimulus sequence information can be selected from a sequence memory array, and stimulus sequence information can be received from the sequence memory array at a stimulus generator selector. A generator select signal can be provided to a stimulus generator of a closed loop neuromodulator using the stimulus sequence information and a stimulus duration signal, wherein the generator select signal can include stimulus type information related to stimulus pulses generated using the closed loop neuromodulator.

PRIORITY AND RELATED APPLICATIONS

This application is a continuation application of U.S. Nonprovisionalpatent application Ser. No. 12/583,582 filed Aug. 21, 2009, and claimsthe benefit under 35 U.S.C 119(e) of the following U.S. ProvisionalPatent Applications, the contents of which are incorporated herein byreference in their entirety:

-   U.S. Provisional Patent Application Ser. No. 61/090,966 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/090,968 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,118 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,112 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,105 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,101 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,099 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,094 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,087 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,082 filed Aug.    22, 2008,-   U.S. Provisional Patent Application Ser. No. 61/091,078 filed Aug.    22, 2008,-   and U.S. Provisional Patent Application Ser. No. 61/091,074 filed    Aug. 22, 2008.

TECHNICAL FIELD

The present subject matter relates generally to sleep therapy and morespecifically to a stimulus sequencer for a closed loop neuromodulator.

BACKGROUND

Sleep disorders have recently become the focus of a growing number ofphysicians. Sleep disorders include obstructive sleep apnea, centralsleep apnea, complex sleep apnea, snoring, restless leg syndrome (RLS),periodic limb movement (PLM), sudden infant death syndrome (SIDS), andrelated neurological and physiological events or conditions occurringduring sleep. Many hospitals and clinics have established sleeplaboratories (sleep labs) to diagnose and treat sleep disorders. In thesleep laboratories, practitioners use instrumentation to monitor andrecord a patient's sleep states, stages and behaviors during sleep.Practitioners rely on these recordings to diagnose patients andprescribe proper therapies.

A goal of addressing sleep disorders is to help a person sleep better.Another goal of addressing sleep disorders is to help a person livelonger. It is well known that various undesirable behaviors often occurduring sleep such as snoring, apneas, abnormal breathing, Bruxism (teethclenching and grinding) and the like. It is further known that thesedisorders and other undesirable behaviors can not only lead toinsufficient amounts of sleep or fatigue but are also linked toco-morbidities such as obesity, diabetes, hypertension, cardiacdiseases, stroke and SIDS, all of which can lead to a pre-mature death.Serious efforts are being made to reduce or eliminate these undesirabledisorders and behaviors in part because of these co-morbidity concerns.

Various stimulation controllers/systems are available in the art foraltering undesirable behavior during sleep. These controllers/systemsmay be used to control a stimulation device. U.S. Pat. No. 5,540,733 toTesterman et al. discloses “[a] method for treating obstructive sleepapnea in a patient by electrical stimulation of muscles in the upperairway.” In U.S. Pat. No. 7,115,097 to Johnson, “[a] notification systemmonitors changes in air flow channeled between a positive air pressuregenerator and a CPAP mask supplying positive airway pressure to apatient during treatment of sleep apnea.” In U.S. Pat. No. 6,544,199 toMorris, “[a] system is provided for monitoring an undesired behavioraldisorder such as Bruxism, jaw clenching, or snoring.” In anotherexample, U.S. Patent Publication No. US2006/0145878 to Lehrman et al.discloses “[a] System and method for treating obstructive sleep apnea byterminating an obstructive sleep apnea event before the cessation ofbreathing occurs.”

It is well known that several states of sleep exist and involve varyinglevels of consciousness. It is further well known that the beneficialeffects of sleep improve when it is uninterrupted. To the extent thatthe above controllers/systems and associated stimulation devices alter apatient's sleep state or in a worst-case scenario actually awaken apatient, the devices have gone too far. While they may have stopped theundesirable behavior, they have neither helped a person sleep better norhave they helped a person to live longer.

SUMMARY

There is a need to provide an apparatus and method that controls thestimulation of the central nervous system sufficiently to interrupt anundesirable neurological and/or sleep behavior by a means universallysensed by most patients where the device avoids significantly changingsleep states and certainly avoids waking a patient.

With the present subject matter, sleep therapy devices may be used inthe absence of sleep lab personnel and practitioners who often make theadjustments to the devices on an ongoing basis. These adjustmentsinclude the initial patient setup, the intensity of stimulation, and thetype of stimulation. Additional adjustment is necessary when the type ofstimulation is varied to assure that the controlling device is correctlyconfigured. Certain optimization adjustments are also made bypractitioners. Thus, there is a need for an apparatus and method thatautomatically and autonomously optimizes its operation, as discussed inmore detail below, so that there is no need for periodic patient orphysician intervention.

The initial setup of the patient involves configuring the device basedon an assessment of the patient with regard to the neurological andphysiological condition of the patient. This process is somewhat of abig picture accuracy adjustment that makes sure the device is configuredto properly address the correct sleep disorder taking into considerationthe physical attributes and condition of the patient. In the absence ofa practitioner, there is a need for a device with automatic andautonomous setup capabilities so the device can be correctly configuredat the outset of treatment and begin to properly treat the patient.

A better understanding of the present subject matter may be gained fromthe following discussion regarding the adjustments relating to theintensity and type of stimulation. If the types of stimuli are appliedwith the same intensity, timing and duration on a repeated basis, thereis a natural tendency to become habituated to them and then there is noreasonable assurance that the next stimulus is going to be effective tocause the patient to start resuming normal respiration. In a similarfashion, if the same type of stimulus is repeatedly applied, there isalso a tendency to become habituated. In light of the precision neededin treating patients to avoid cortical arousal, there is a need toperiodically, frequently or constantly vary the stimuli intensity andtype in order for the stimuli to be noticed by the patient's centralnervous system. In the absence of a practitioner, there is a need forthe device to provide auto-adjusting, auto-optimizing and auto-dosing.

As different types of stimuli are used in sleep labs and in patient'shomes, practitioners may use different controllers for differentstimuli. Where a single controller is used, adjustments assure propersignals are sent to the stimulating device. As discussed above, in theabsence of a practitioner, there is a need for auto-optimizing and thusa need for a device to be able to vary the stimuli provided. As such,there is also a need for a controller that is auto-adjusting so that thecontroller automatically adjusts for the different types andsensitivities of sensors and transducers that are being connected to aclosed loop neuromodulator.

As also mentioned, practitioners often make certain optimizingadjustments to a controller to optimize the treatment being provided. Inthe absence of a practitioner, there is also a need for an apparatus andmethod that is auto-optimizing so that the controller automatically andimmediately optimizes the application of therapy when physiologicalpatient conditions change from day-to-day or between applications ofindividual therapies during each night sleep or session.

As sleep therapy devices continue to be used in the homes of patients,issues of “electronic smog” and electrostatic shock become a concern aspatients handle and wear the devices, especially in dry climates andduring the winter. Additionally, there is an increasing use of wirelesstechnology such as wireless telephone transmissions, wireless routers,cordless phone systems, remote control burglar alarm devices, remotecontrol toys, etc that could interfere with a sleep therapy device.Thus, there is also a need to provide an apparatus that iselectronically hardened against the electronically harsh and hostileenvironments often encountered in modern life, modern homes and modernsleeping environments.

Additionally, patients' homes and sleeping environments arenon-controlled environments. In a sleep lab or clinic, the same stimulusmay be applied. In a home environment the sleeping patient may besubjected to external stimulus, passing trains, noisy bugs and kids, TVrunning while sleeping, snoring bed partner, noisy neighbors, honkingcars, conversations by non sleeping people, high speed trains, cartraffic, etc. the possibilities for sleeping patient arousal arecountless. In certain predictable environments, the patents' centralnervous system (CNS) has already gotten used to certain stimulus and haslearned over time to tune them out consciously and subconsciously.However, other stimulus, both intermittent and chronic stimulus, aredifficult to overcome including changes in individual patients based onphysiology, mental state (mood etc), sensitivity to air pressure andother atmospheric parameters, sickness, disease, room decorations andbedding (sound dampening measures make the room quieter thus one canhear the stimulus better), time of day, season (people with allergiesand hay fever will have different sensitivities to the stimulus dosagesdepending on their level of allergies or hay fever), noisy bed partners. . . etc.

A robust dosage optimization system works reliably and repeatedly ondifferent patients, with different patient conditions, different moods,sickness, disease, different environments, time of day, locations (onaverage, the city of New York is louder than the city of Bismarck, N.Dak. and the device and the invention has to work equally well in eithercity), and over many years of use, preferably the entire lifespan of ahuman being once they start treatment using this apparatus and method.

Subjects that have an influence on patient's needs to, current andimmediate dosing requirements:

Environmental (sound, noise, etc)

Health (disease, sickness, disability, etc)

Physical condition (earwax in the ear canal, stress, etc)

Physiological (hearing loss, etc)

Neurological (tinnitus, fibromyalgia, etc)

Seasonal (allergies, seasonal noise, etc)

Atmospheric (pressure, heat, humidity, etc)

Thus, there is a need for an apparatus and method that is capable ofperiodically, constantly and prescriptively changing (varying) anapplied stimulus to interrupt a sleep disorder event. For examplechanging a stimulus type, stimulus level, stimulus rate, stimulusduration, stimulus sequence, level escalation, rate escalation durationescalation, or combination thereof.

There is a need to provide an apparatus and method to further ensurepatient compliance with physicians prescribed treatments.

There is a need to provide an apparatus and method that controls thestimulation of the central nervous system sufficiently to interrupt anundesirable neurological and/or sleep behavior by a means universallysensed by most patients where the device avoids significantly changingsleep states and certainly avoids waking a patient. There is a need inthe art to provide precise dosing of patients.

There is a need to provide an apparatus and method that controls thestimulation of the central nervous system sufficiently to interrupt anundesirable neurological and/or sleep behavior by a means universallysensed by most patients where the device avoids significantly changingsleep states and certainly avoids waking a patient.

There is a need to provide an apparatus that is capable of being usedwith a wide range of transducers. Additionally, there is a need for thisdevice to be protected against electronically hostile environmentsinvolving EMI and ESD commonly found in homes.

There is a need to provide an apparatus and method that controls thestimulation of the central nervous system sufficiently to interrupt anundesirable neurological and/or sleep behavior by a means universallysensed by most patients where the device avoids significantly changingsleep states and certainly avoids waking a patient.

Also, as sleep therapy becomes more common, the devices used to treat itare beginning to extend beyond use in sleep labs and are often usedright in a patient's own home. The sleep therapy devices are thus usedin the absence of sleep lab personnel and practitioners who can read andinterpret the device. Thus, there is a need for a device that indicatesthe input it is receiving, the functions it is performing, and theoutput it is transmitting. Moreover, devices that are used in homes mayneed to be initially set to function properly for given patientparameters. In these situations, a practitioner may need to use a sleepdevice in conjunction with a more sophisticated polysomnograph machine(PSG) in order to ensure that it is properly set. Thus, there is a needfor the device to be compatible with a polysomnograph machine.

There is a need to provide an apparatus and method that controls thestimulation of the central nervous system sufficiently to interrupt anundesirable neurological and/or sleep behavior by a means universallysensed by most patients where the device avoids significantly changingsleep states and certainly avoids waking a patient.

Also, as sleep therapy becomes more common, the devices used to treat itare beginning to extend beyond use in sleep labs and are often usedright in a patient's own home. The sleep therapy devices are thus usedin the absence of sleep lab personnel and practitioners who often makethe adjustments to the devices on an ongoing basis. Thus, there is aneed in the art for a device that can properly operate and control aclosed loop neuromodulator.

Finally, there is a need to provide an apparatus that is comfortable towear, easy to set-up, and simple to use to further its ability to avoidalteration of sleep states.

Certain embodiments of the present subject matter provide a closed loopneuromodulator that by means of detecting the presence or absence ofcertain biological sensor signals provides dynamically and preciselydosed stimulation of the central nervous system in general and to thehuman central nervous system in specific by means of immediatebiological feedback and appropriate stimulation of one or more of thefive human senses.

In one embodiment, a closed loop neuromodulator includes an EMI/ESDhardened sensor interface, an activity detector, a stimulus timer, astimulus escalator a stimulus generator, a stimulus sequencer, and anEMI/ESD hardened transducer driver.

In one embodiment, a method for dosage optimization in a closed loopneuromodulator includes monitoring a patient for an activity indicatinga sleep disorder, applying a first stimulus based on a stored stimulusparameter to a patient once a sleep disorder is detected, rechecking thepatient for continued activity indicating a sleep disorder, determiningif the stimulus was an over stimulation or an under stimulation, anddecreasing, increasing, or maintaining the stimulus parameter.

In another embodiment, determining whether the stimulus was an overstimulation or an under stimulation includes querying whether thepatient has continued activity and if not, whether the stimulus was afirst stimulus. In another embodiment, the method includes decreasingthe stimulus parameter when the stimulus was an over stimulus andrecording and storing a new stimulus parameter. In yet anotherembodiment, the method includes increasing the stimulus parameter whenthe stimulus was an under stimulus and recording and storing a newstimulus parameter. In still another embodiment, the method includesbypassing the increasing or decreasing of the stimulus parameter whenthe stimulus was an optimal stimulus.

In another embodiment, a diagnostic method of use of a stimulationcontroller includes connecting a closed loop neuromodulator to apatient, connecting a PSG machine to the stimulation controller,connecting a remote terminal to the stimulation controller, receivinginformation regarding the patient and the controller from a diagnosticinterface and a PSG machine, and adjusting the parameters of the closedloop neuromodulator to optimize the controller for stimulating a patientor range of patients.

In another embodiment, a therapeutic method of use of a stimulationcontroller includes connecting a closed loop neuromodulator to a patientwherein the controller auto-adjusts and proceeds to optimize dosagebased on a limited range of available parameters provided by a sleepprofessional.

In one embodiment, a virtual device development system like NationalInstruments CompactRIO running code that has been developed usingNational Instruments LabVIEW virtual development system including thewire terminations for the sensor and for the transducer is provided.

In another embodiment, a field programmable gate array (FPGA) with aninternal processor, read-only memory (ROM), random access memory (RAM),reset management, an oscillator, an analog-to-digital converter, adigital-to-analog converter, configuration string, and wire terminalsfor the sensor and for the transducer is provided.

In another embodiment, a mixed signal micro controller like one of theColdFire product line available from Freescale Semiconductors isexecuting code, command and algorithms developed with an appropriatesoftware compiler is provided.

In another embodiment, a discrete circuit assembly consisting of aprinted circuit board (PCB) populated with electronic componentsincluding the wire terminations for the sensor and for the transducer isprovided.

In another embodiment, software residing inside a personal computer (PC)is executing code, command and algorithms developed with an appropriatesoftware development system like C, C+ or C++, with an attached dataacquisition system including the wire terminations for the sensor andfor the transducer are provided.

In another embodiment, a custom integrated circuit like the one that isavailable from semiconductor houses is executing code, commands andalgorithms developed on a silicon computer aided design (CAD) platformincluding the wire terminations for the sensor and for the transducer isprovided.

In Example 1, a stimulus sequencer for generating a sleep therapystimulus waveform for a patient includes a sequence address generatorconfigured to receive a stimulus start signal from a timer of a closedloop neuromodulator and to provide an address related to a stimulussequence of the sleep therapy, a sequence memory array coupled to thesequence address generator, the sequence memory array configured toselect stimulus sequence information related to the address, a stimulusgenerator selector coupled to the sequence memory array, the stimulusgenerator selector configured to receive the stimulus sequenceinformation from the sequence memory array, to receive a stimulusduration signal from the timer of the closed loop neuromodulator, and toprovide a generator select signal to a stimulus generator of the closedloop neuromodulator using the stimulus sequence information and thestimulus duration signal, the generator select signal including stimulustype information related to stimulus pulses generated using the closedloop neuromodulator, and wherein the sleep therapy stimulus waveformincludes a sequence of one or more stimulus types.

In Example 2, the closed loop neuromodulator of Example 1 is optionallyconfigured to provide, in response to the stimulus start signal, a firststimulus to the patient using information from the stimulus sequencer,the first stimulus configured to not interrupt a detected sleep disorderevent, and the closed loop neuromodulator of Example 1 is optionallyconfigured to provide, following the first stimulus, a second stimulusto the patient using information from the stimulus sequencer, the secondstimulus having more energy than the first stimulus and configured tointerrupt the detected sleep disorder event.

In Example 3, the stimulus sequencer of any one or more of Examples 1-2optionally includes a sequence address register configured to receive orprovide stimulus address information using a control bus of the closedloop neuromodulator.

In Example 4, the stimulus sequencer of any one or more of Examples 1-3optionally includes a sequence load control register configured toreceive or provide a sequence load control command using a control busof the closed loop neuromodulator.

In Example 5, the stimulus sequencer of any one or more of Examples 1-4optionally includes a sequence load address register configured toreceive or provide a sequence address load command using a control busof the closed loop neuromodulator.

In Example 6, the stimulus sequencer of any one or more of Examples 1-5optionally includes a sequence load data register configured to receiveor provide a sequence data load command using a control bus of theclosed loop neuromodulator.

In Example 7, the sequence memory array of any one or more of Examples1-6 is optionally configured to select a stimulus sequence from a groupcomprising at least one of a fixed sequence, a sequential sequence, acircular sequence, a random sequence, a periodic sequence, a customsequence, a patterned sequence, or a continuous sequence.

In Example 8, a system, for generating a sleep therapy stimulus waveformfor a patient, of any one or more of Examples 1-7 optionally includes asensor configured to detect information indicative of respiration from apatient, a closed loop neuromodulator configured to optimize sleeptherapy for the patient, the closed loop neuromodulator including astimulus sequencer configured to provide a generator select signal to astimulus generator of the closed loop neuromodulator, the stimulussequencer including a sequence address generator configured to receive astimulus start signal from a timer of a closed loop neuromodulator andto provide an address related to a stimulus sequence of the sleeptherapy, a sequence memory array coupled to the sequence addressgenerator, the sequence memory array configured to select stimulussequence information related to the address, a stimulus generatorselector coupled to the sequence memory array, the stimulus generatorselector configured to receive the stimulus sequence information fromthe sequence memory array, to receive a stimulus duration signal fromthe timer of the closed loop neuromodulator, and to provide a generatorselect signal to a stimulus generator of the closed loop neuromodulatorusing the stimulus sequence information and the stimulus durationsignal, the generator select signal including stimulus type informationrelated to stimulus pulses generated using the closed loopneuromodulator, wherein the sleep therapy stimulus waveform includes asequence of one or more stimulus types, and a sequence address registerconfigured to receive or provide stimulus address information using acontrol bus of the closed loop neuromodulator, a sequence load controlregister configured to receive or provide a sequence load controlcommand using a control bus of the closed loop neuromodulator, asequence load address register configured to receive or provide asequence address load command using a control bus of the closed loopneuromodulator, and a sequence load data register configured to receiveor provide a sequence data load command using a control bus of theclosed loop neuromodulator, wherein the sequence memory array isconfigured to select a stimulus sequence from a group comprising atleast one of a fixed sequence, a sequential sequence, a circularsequence, a random sequence, a periodic sequence, a custom sequence, apatterned sequence, or a continuous sequence, wherein the closed loopneuromodulator is configured to provide, in response to the stimulusstart signal, a first stimulus to a transducer using information fromthe stimulus sequencer, the first stimulus configured to not interrupt adetected sleep disorder event, wherein the closed loop neuromodulator isconfigured to provide, following the first stimulus, a second stimulusto the transducer using information from the stimulus sequencer, thesecond stimulus having more energy than the first stimulus andconfigured to interrupt the detected sleep disorder event, and whereinthe transducer is configured to deliver the first and second stimuli tothe patient.

In Example 9, the sensor of any one or more of Examples 1-8 optionallyincludes at least one of a thermocouple, a thermistor, an air pressuretransducer, an electrode, a respiratory effort belt, or agyro/piezoelectric sensor, and the transducer of any one or more ofExamples 1-8 optionally includes at least one of an acoustic transducer,a tactile mechanical agitator, an ocular stimulator, an electricalstimulator, a thermal stimulator, or an ultrasonic stimulator configuredto modulate an audible signal onto an ultrasonic sound carrier.

In Example 10, a method, for generating a sleep therapy stimuluswaveform for a patient, of any one or more of Examples 1-9 optionallyincludes receiving a stimulus start signal from a timer of a closed loopneuromodulator, providing an address related to a stimulus sequence ofthe sleep therapy, selecting stimulus sequence information related tothe address from a sequence memory array, receiving the stimulussequence information from the sequence memory array at a stimulusgenerator selector, receiving a stimulus duration signal from the timerof the closed loop neuromodulator at the stimulus generator selector,providing a generator select signal to a stimulus generator of theclosed loop neuromodulator using the stimulus sequence information andthe stimulus duration signal, the generator select signal includingstimulus type information related to stimulus pulses generated using theclosed loop neuromodulator, and wherein the sleep therapy stimuluswaveform includes a sequence of one or more stimulus types.

In Example 11, the method of any one or more of Examples 1-10 optionallyincludes providing, in response to the stimulus start signal, a firststimulus to the patient using the generator select signal, the firststimulus configured to not interrupt a detected sleep disorder event;and providing, following the first stimulus, a second stimulus to thepatient using the generator select signal, the second stimulus havingmore energy than the first stimulus and configured to interrupt thedetected sleep disorder event.

In Example 12, the method of any one or more of Examples 1-11 optionallyincludes receiving or providing stimulus address information using asequence address register coupled to a control bus of the closed loopneuromodulator.

In Example 13, the receiving or providing of any one or more of Examples1-12 optionally includes receiving stimulus address information from auser or providing stimulus address information to the user.

In Example 14, the method of any one or more of Examples 1-13 optionallyincludes receiving or providing a sequence load control command using asequence load control register coupled to a control bus of the closedloop neuromodulator.

In Example 15, the receiving or providing of any one or more of Examples1-14 optionally includes receiving a sequence load control command froma user or providing a sequence load control command to a user.

In Example 16, the method of any one or more of Examples 1-15 optionallyincludes receiving or providing a sequence address load command using asequence load address register coupled to a control bus of the closedloop neuromodulator.

In Example 17, the receiving or providing of any one or more of Examples1-16 optionally includes receiving a sequence address load command froma user or providing a sequence address load command to a user.

In Example 18, the method of any one or more of Examples 1-17 optionallyincludes receiving or providing a sequence data load command using asequence load data register coupled to a control bus of the closed loopneuromodulator.

In Example 19, the receiving or providing of any one or more of Examples1-18 optionally includes receiving a sequence data load command from auser or providing a sequence data load command to a user.

In Example 20, the selecting stimulus sequence information related tothe address of any one or more of Examples 1-19 optionally includesselecting a stimulus sequence from a group optionally includes at leastone of a fixed sequence, a sequential sequence, a circular sequence, arandom sequence, a periodic sequence, a custom sequence, a patternedsequence, or a continuous sequence.

Auto adjusting is the method by which the apparatus automatically andautonomously adjusts itself to the patient and to different sensor andtransducer sensitivities.

Auto optimizing is the method by which the apparatus automatically andconstantly optimizes its operation constantly during operation to theimmediate and sometimes different patient conditions.

Auto dosing is the method by which the apparatus automatically andautonomously doses the right amount of therapeutic stimuli according tothe needs of the individual patient for optimal comfort and performance.

The apparatus issues specific doses and types of stimuli to the patientuntil the resumption of breathing has been detected.

A neuromodulator includes a controller that applies stimuli and where apatient's central nervous system forms a feedback loop to assist in themodulation or adjustment of the stimuli.

While the present disclosure is directed toward treatment of sleepdisorders, further areas of applicability will become apparent from thedescription provided herein. It should be understood that thedescription and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of the presentdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The forgoing features, objects and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription, especially when considered in conjunction with theaccompanying drawings in which like the numerals in the several viewsrefer to the corresponding parts:

FIG. 1A is a configuration diagram of a sleep diagnostic closed loopneuromodulator in place on a sleep patient according to one example ofthe present subject matter.

FIG. 1B is a configuration diagram of a sleep therapy closed loopneuromodulator in place on a sleep patient according to one example ofthe present subject matter.

FIG. 2A illustrates generally an electrical block diagram of a sleepdiagnostic closed loop neuromodulator.

FIG. 2B is an electrical block diagram of the sleep therapy closed loopneuromodulator according to one example of the present subject matter.

FIG. 3A illustrates generally an electrical block diagram of an EMI/ESDHardened Sensor Interface.

FIG. 3B is a detailed electrical block diagram of an EMI/ESD HardenedSensor Interface according to one example of the present subject matter.

FIG. 3C is an electrical schematic diagram of an EMI/ESD Hardened SensorInterface according to one example of the present subject matter.

FIG. 3D is an electrical timing diagram of an analog to digitalconversion of an airflow sensor signal by an EMI/ESD Hardened SensorInterface.

FIG. 4A illustrates generally an electrical block diagram of an ActivityDetector.

FIG. 4B is a detailed electrical block diagram of an Activity Detectoraccording to one example of the present subject matter.

FIG. 4C is a timing diagram of an apnea detection of an ActivityDetector according to one example of the present subject matter.

FIG. 5A illustrates generally an electrical block diagram of a StimulusTimer.

FIG. 5B is a detailed electrical block diagram of a Stimulus Timeraccording to one example of the present subject matter.

FIG. 6A illustrates generally an electrical block diagram of a StimulusSequencer.

FIG. 6B is a detailed electrical block diagram of a Stimulus Sequenceraccording to one example of the present subject matter.

FIG. 6C is timing diagram of various Stimulus generator sequences of aStimulus Sequencer according to one example of the present subjectmatter.

FIG. 7A illustrates generally an electrical block diagram of a StimulusGenerator.

FIG. 7B is a detailed electrical block diagram of a Stimulus Generatoraccording to one example of the present subject matter.

FIG. 8A illustrates generally an electrical block diagram of a StimulusEscalator.

FIG. 8B is a detailed electrical block diagram of a Stimulus Escalatoraccording to one example of the present subject matter.

FIG. 9A illustrates generally an electrical block diagram of an EMI/ESDHardened Transducer Driver.

FIG. 9B is a detailed electrical block diagram of an EMI/ESD HardenedTransducer Driver according to one example of the present subjectmatter.

FIG. 9C is an electrical schematic diagram of an EMI/ESD HardenedTransducer Driver.

FIG. 10A illustrates generally an electrical block diagram of aDiagnostic Indicators and PSG Interface.

FIG. 10B is an detailed electrical block diagram of a DiagnosticIndicators and PSG Interface according to one example of the presentsubject matter.

FIG. 11A illustrates generally an electrical block diagram of a DeviceController & Data Logger.

FIG. 11B is detailed electrical block diagram of a Device Controller &Data Logger according to one example of the present subject matter.

FIG. 12A illustrates generally an electrical block diagram forimplementation in a virtual product development platform of a sleepdiagnostic closed loop neuromodulator according to one example of thepresent subject matter.

FIG. 12B illustrates generally an electrical block diagram forimplementation in a Field Programmable Gate Array (FPGA) of a sleepdiagnostic closed loop neuromodulator according to one example of thepresent subject matter.

FIG. 12C illustrates generally an electrical block diagram forimplementation in a Mixed Signal Micro Controller of a sleep diagnosticclosed loop neuromodulator according to one example of the presentsubject matter.

FIG. 12D illustrates generally an electrical block diagram forimplementation in a Custom Integrated Circuit (IC) of a sleep diagnosticclosed loop neuromodulator according to one example of the presentsubject matter.

FIG. 12E illustrates generally an electrical block diagram forimplementation in a Discrete Component Printed Circuit Board Assembly(PCB) of a sleep diagnostic closed loop neuromodulator according to oneexample of the present subject matter.

FIG. 12F illustrates generally an electrical block diagram for softwarebased implementation in a Personal Computer of a sleep diagnostic closedloop neuromodulator according to one example of the present subjectmatter.

FIG. 12G illustrates generally an electrical block diagram forimplementation in a virtual product development platform of a sleeptherapy closed loop neuromodulator according to one example of thepresent subject matter.

FIG. 12H illustrates generally an electrical block diagram forimplementation in a Field Programmable Gate Array (FPGA) of a sleeptherapy closed loop neuromodulator according to one example of thepresent subject matter.

FIG. 12I illustrates generally an electrical block diagram forimplementation in a Mixed Signal Micro Controller of a sleep therapyclosed loop neuromodulator according to one example of the presentsubject matter.

FIG. 12J illustrates generally an electrical block diagram forimplementation in a Custom Integrated Circuit (IC) of a sleep therapyclosed loop neuromodulator according to one example of the presentsubject matter.

FIG. 12K illustrates generally an electrical block diagram forimplementation in a Discrete Component Printed Circuit Board Assembly(PCB) of a sleep therapy closed loop neuromodulator according to oneexample of the present subject matter.

FIG. 12L illustrates generally an electrical block diagram for softwarebased implementation in a Personal Computer (PC) of a sleep therapyclosed loop neuromodulator according to one example of the presentsubject matter.

FIG. 13A illustrates generally a diagram depicting the stimulusparameters of a closed loop neuromodulator.

FIG. 13B illustrates generally a timing diagram depicting stimulationtiming.

FIG. 14A illustrates generally a timing diagram depicting overstimulation.

FIG. 14B illustrates generally a timing diagram depicting optimalstimulation.

FIG. 14C illustrates generally a timing diagram depicting understimulation.

FIG. 15A illustrates generally a timing diagram depicting stimulusescalation without repeats of the previous stimulus.

FIG. 15B illustrates generally a timing diagram depicting stimulusescalation with repeats of the previous stimulus.

FIG. 16A illustrates generally a diagram depicting stimulus leveloptimization.

FIG. 16B illustrates generally a diagram depicting stimulus durationoptimization.

FIG. 16C illustrates generally a timing diagram depicting stimulus rateoptimization.

FIG. 17 is a detailed flow-chart for the Stimulus Dosage Optimization ofthe closed loop neuromodulator according to one example of the presentsubject matter.

FIG. 18A is a detailed electrical schematic diagram of the analogsection of a simplified discrete component embodiment of a closed loopneuromodulator according to one example of the present subject matter.

FIG. 18B is a detailed electrical schematic diagram of the digitalsection of a simplified discrete component embodiment of a closed loopneuromodulator according to one example of the present subject matter.

FIG. 18C is a detailed electrical schematic diagram of the levelescalation section of a simplified discrete embodiment of a closed loopneuromodulator according to one example of the present subject matter.

FIG. 18D is a detailed electrical schematic diagram of the power supplysection of a simplified discrete component embodiment of a closed loopneuromodulator according to one example of the present subject matter.

FIG. 19 illustrates generally a diagram depicting a StimulationBio-Feedback Loop of a closed loop neuromodulator.

DETAILED DESCRIPTION

The following detailed description relates to a closed loopneuromodulator directed toward treating patients with sleep disorders.The closed loop neuromodulator is more particularly directed atstimulating a patient to interrupt and terminate an undesired sleepbehavior or condition such as snoring, obstructive sleep apnea, centralsleep apnea, complex sleep apnea, snoring, restless leg syndrome (RLS),periodic limb movement (PLM), Bruxism (teeth grinding and clenching),sudden infant death syndrome (SIDS) and other neurological disorders notnecessarily related to sleep. The closed loop neuromodulator may be usedin conjunction with a sensor and a transducer affixed to a patient. Thesensor transmits respiratory information to the closed loopneuromodulator that analyzes the information, adjusts to the patientduring a first use, applies a proper and precise stimulation type anddosage, and optimizes its operation and transducer output dosingdepending on the past and present sensor information received. Thedosage may be adjusted based on at least the following parameters: 1.Stimulus Type, 2. Stimulus Rate, 3. Stimulus Duration, 4. StimulusLevel, 5. Stimulus Escalation, 6. Stimulus Sequence.

The controller counts the amount of applied pulses and measures the timeobserved to cause the resumption of breathing in a sleeping person. Thenumber of pulses and amount of time elapsed until the resumption ofbreathing is a direct measure for the effectiveness of the applied pulsestimuli. The number of pulses, intensity of stimulation and timeobserved to cause the resumption of breathing must be at a minimum inorder to obtain optimal results. When the number of stimuli pulsesexceeds a limit, then the signal level of the new stimuli for the nextbreathing cessation event increases automatically. When the number ofstimuli pulses falls below a lower limit, then the signal level of thenew stimuli for the next breathing cessation event reducesautomatically.

The following detailed description includes discussion of sensors andtransducers affixed to patients. Additionally, elements of a closed loopneuromodulator are discussed including an electromagneticinterference/electrostatic discharge (EMI/ESD) hardened sensorInterface, an Activity Detector, a stimulus timer, a stimulus escalator;a stimulus generator, a stimulus sequencer, and an EMI/ESD hardenedtransducer driver. Information regarding the waveforms and timingsignals received and generated are also included.

The present invention can be readily understood from FIGS. 1 through 19.

FIG. 1A shows an overall use and configuration of a sleep diagnosticclosed loop neuromodulator according to one example of the presentsubject matter. A typical sleep diagnostic patient 1 suffering from asleep disorder has been outfitted with a sensor 2 to measure respiratoryeffort. A pair of sensor output wire leads 3 connects the sensor to theinput of the controller device 4. The output of the controller 4connects via a pair of wire leads 5 to the transducer 6. Another outputof the controller 4 connects via a set of wire leads 7 to a sleep labPSG machine 8. A remote diagnostic input/output port of the controller 4connects via a set of wire leads 9 to a remote diagnostic terminal 14.

Preferably, the sensor 2 of FIG. 1A is a piezoelectric sensorconstructed in accordance with the teachings of U.S. Pat. Nos. 5,311,875and 6,254,545 to Stasz, the teachings of which are hereby incorporatedby reference as if fully set forth herein. Those skilled in the art willunderstand and appreciate that various sensors are known including, butnot limited to thermocouples, thermistors, air pressure transducers,electrodes and respiratory plethysmography inductance (RIP) belts andthat these sensors are within the scope of the invention.

The transducer shown in FIG. 1A is preferably an aural ear-bud typetransducer, a tactile mechanical agitator, an ocular stimulator, or anultrasonic stimulator based on modulating an audible signal onto anultrasonic sound carrier. For example, the transducer may be an agitatoras described in the U.S. Provisional Patent Application titled Agitatorto Stimulate the Central Nervous System, filed on May 2, 2008 with Ser.No. 61/049,802, the contents of which are hereby incorporated byreference herein. Those skilled in the art will understand andappreciate that various transducers exist for stimulating centralnervous systems and are thus within the scope of the present invention.

FIG. 1B shows an overall use and configuration of a sleep therapy closedloop neuromodulator according to one example of the present subjectmatter. A sleep therapy patient 1 suffering from a sleep disorder hasbeen outfitted with a sensor 2 to measure respiratory effort. A pair ofsensor output wire leads 3 connects the sensor to the input of thecontroller device 4. The output of the controller 4 connects via a pairof wire leads 5 to the transducer 6.

Preferably, the sensor 2 of FIG. 1B is a piezoelectric sensorconstructed in accordance with the teachings of U.S. Pat. Nos. 5,311,875and 6,254,545 to Stasz, the teachings of which are hereby incorporatedby reference as if fully set forth herein. Those skilled in the art willunderstand and appreciate that various sensors are known including, butnot limited to thermocouples, thermistors, air pressure transducers,electrodes and respiratory effort belts, gyro/piezoelectric sensors andthat these sensors are within the scope of the invention.

The transducer shown in FIG. 1B is preferably an aural ear-bud typetransducer, a tactile mechanical agitator, an ocular stimulator, or anultrasonic stimulator based on modulating an audible signal onto anultrasonic sound carrier. For example, the transducer may be an agitatoras described in the U.S. Provisional Patent Application titled Agitatorto Stimulate the Central Nervous System, filed on May 2, 2008 with Ser.No. 61/049,802, the contents of which are hereby incorporated byreference herein. Those skilled in the art will understand andappreciate that various transducers exist for stimulating centralnervous systems and are thus within the scope of the present invention.

Referring to FIG. 2A, there is indicated generally by numeral 4 a blockdiagram of the sleep diagnostic closed loop neuromodulator along with asensor 2 and a transducer 6. Attached to the sensor and sleep diagnosticclosed loop neuromodulator is a pair of wire terminations 3 via whichthe sleep diagnostic closed loop neuromodulator receives the sensoroutput. Attached to the transducer and sleep diagnostic closed loopneuromodulator is a pair of wire terminations 5 via which the sleepdiagnostic closed loop neuromodulator transmits the transducer input. Asleep lab PSG machine 8 connects to the controller 4 connects via a setof wire leads 7. A remote diagnostic terminal 14 connects to thecontroller 4 via a set of wire leads 9. Furthermore the sleep diagnosticclosed loop neuromodulator indicated generally by numeral 4 contains anEMI/ESD hardened sensor Interface 10, an activity detector 20, astimulus timer 30, a stimulus sequencer 40, a stimulus generator 50, astimulus escalator 60, an EMI/ESD hardened transducer driver 70, adiagnostic indicator and PSG interface 80, and a device controller anddata logger 90.

Referring to FIG. 2B, there is indicated generally by numeral 4 a blockdiagram of the sleep therapy closed loop neuromodulator along with asensor 2 and a transducer 6. Attached to the sensor and sleep therapyclosed loop neuromodulator is a pair of wire terminations 3 via whichthe sleep therapy closed loop neuromodulator receives the sensor output.Attached to the transducer and sleep therapy closed loop neuromodulatoris a pair of wire terminations 5 via which the sleep therapy closed loopneuromodulator transmits the transducer input. Furthermore the sleeptherapy closed loop neuromodulator indicated generally by numeral 4contains an EMI/ESD hardened sensor Interface 10, an activity detector20, a stimulus timer 30, a stimulus sequencer 40, a stimulus generator50, a stimulus escalator 60, an EMI/ESD hardened transducer driver 70, adiagnostic indicator and PSG interface 80, and a device controller anddata logger 90.

EMI/ESD Hardened Sensor Interface

Even though most countries have legal requirements that mandate EMCcompliance, electronic devices must still work correctly when subjectedto certain amounts of electromagnetic interference (EMI), and should notemit EMI, which could interfere with other equipment. This issue isknown in the industry as self-compatibility and this fact is crucial tothe operation of the invention because of the very low analog biomedicalsignals involved.

A robust sleep therapy system works reliably in a modern harsh andhostile environment in close proximity to cell phone transmissions,wireless internet transmitters, wireless phone system transmitters, etc.Modern environments, even home environments have high concentration ofEMI and RFI especially in the 60 Hz/120 Hz due to home power wiring andfluorescent, compact fluorescent lighting and switch mode power suppliesoperating in home appliances. Additionally, wireless technology such aswireless telephone transmissions, wireless routers, cordless phonesystems, remote control burglar alarm devices, remote control toys, andthe like may emit EMI. Issues of self-compatibility are also a concernand involve minimizing the emission of EMI that could interfere withother portions of the device or other equipment. Thus, EMI that couldinterfere with a sleep device is a concern, but the EMI emitted by thedevice is also a concern. ESD hardening protects sensitive electronicsdue to common and regular handling of the product containing thesensitive electronics in a standard home environment where staticdischarges are common, especially during the winter seasons in colderclimate zones and during the dry seasons in warmer climate zones.

EMI/ESD hardening against the aforementioned offenders not onlysatisfies domestic and international requirements on emissions andsusceptibility but also results in robust operation, cleaner internalsignals, improved signal to noise ratio (SNR) and greater dynamic range.

In one embodiment, an EMI/ESD hardened sensor interface includes asensor input connector, at least one EMI/RFI filter, a grounded metalshield, an ESD protection device, a supply filtered balanced signalamplifier, a supply filtered signal filter, and a supply filtered analogto digital converter.

In another embodiment, the EMI/ESD hardened sensor interface the EMI/RFIfilter includes an external EMI/RFI filter and an internal EMI/RFIfilter. In another embodiment, the external EMI/RFI filter is situatedalong the signal path outside the grounded metal shield. In yet anotherembodiment, the internal EMI/RFI filter is situated along the signalpath inside the grounded metal shield. In yet another embodiment, eachof the elements of the interface are arranged series and the groundedmetal shield encloses the internal EMI/RFI filter, the ESD protectiondevice, the balanced signal amplifier, the signal filter, and the analogto digital converter.

In another embodiment, a method is provided including sensing a behaviorof a patient and filtering, amplifying, and converting the signal froman analog to a digital signal is also provided. In this embodiment, thesignal may also be output to a diagnostic indicator and PSG interface.

Referring to FIG. 3A, there is indicated more specifically by numeral 10an EMI/ESD hardened Sensor Interface. The EMI/ESD hardened sensorInterface 10 is designed to interface with a multitude of differenttypes of respiratory sensors 2. For example, but not limited to,polyvinylidene fluoride film (PVDF) sensors, thermocouples, thermistors,air pressure transducers, electrodes and respiratory effort belts, andgyro/piezoelectric sensors all could be used and connected via the pairof sensor wire terminations 3 to the EMI/ESD hardened sensor Interface10 in order to detect respiratory flow. The term, the causes and thesubject of EMI/ESD are well known to someone skilled in the art. TheEMI/ESD hardened sensor Interface 10 comprises a multitude of EMI/ESDcountermeasures in order to ensure that the sensor signal 3 will bedetected, processed and decoded correctly by this invention withoutsuffering from the adverse affects of EMI and ESD. The EMI/ESD hardenedsensor Interface 10 connects via the digital airflow signal 12 to theactivity detector. Furthermore, the EMI/ESD hardened sensor Interface 10connects via the analog airflow signal 130 to the Diagnostic Indicatorand PSG Interface. A detailed description of the EMI/ESD hardened sensorInterface 10 is provided below and in a separately filed U.S.Provisional Patent Application titled EMI/ESD Hardened Sensor Interfacefor a closed loop neuromodulator, filed on Aug. 22, 2008, the contentsof which are hereby incorporated by reference herein.

The relationship between the analog airflow signal and digital airflowsignal is shown near the bottom of FIG. 3A, where the positive slopingportion of the analog signal is converted to inhalation in the digitalsignal and the negative sloping portion of the analog signal isconverted to exhalation in the digital signal. As discussed above, ananalog airflow activity signal indicating the inhalation and exhalationduration and waveforms may allow a sleep lab practitioner to process thesignal further with a PSG in order to make a more detailed diagnosis. Adigital airflow activity signal indicating the inhalation and exhalationduration may allow a sleep lab practitioner to see directly on themachine, via LED's or other indicators, the patient's respiratoryactivity and possibly at which point of the respiration cycle thepatient has stopped breathing.

An analog airflow activity signal is provided indicating the inhalationduration and exhalation waveforms so that the sleep lab practitioner canprocess the signal further with a PSG in order to make a more detaileddiagnosis.

A digital airflow activity indicator is provided indicating theinhalation duration and exhalation duration so that the sleep labpractitioner can see directly on the machine the patient's respiratoryactivity and possibly at which point of the respiration cycle thepatient has stopped breathing.

Referring to FIG. 3B, there is indicated more specifically by numeral 10a detailed block diagram of an EMI/ESD hardened sensor interfaceaccording to certain embodiments. The sensor interface includes a sensorinput connector 101, external and internal EMI/RFI filters 102, 108, ESDprotection 110, a supply filtered balanced signal amplifier 112, asupply filtered signal filter 114, and a supply filtered analog todigital converter 116. Also included is a metal shield 106.

The sensor input connector 101 provides an input termination for a pairof wire leads 3 extending from an external sensor 2. The sensor inputconnector may consist of an outlet for plugging in the wire leads 3. Thesensor input connector 101 may be connected to an external EMI/RFIFilter via its signal wire pairs 120.

The external EMI/RFI filter 102 provides an initial level of EMI/RFIprotection by filtering out high frequency EMI and RFI. This mayinclude, but is not limited to, EMI and RFI from electronic devices suchas pagers, wireless internet connections, cordless phones, cellularphones, and the like. The external EMI/RFI may be configured to filterout interference ranging from approximately 100 MHz to 10 GHz. Theexternal EMI/RFI filter may be connected to an internal EMI/RFI filtervia wire pairs 122.

The wire pairs 122 extending from the external EMI/RFI filter maypenetrate the wall of a metal shield 106 and further extend to theinternal EMI/RFI filter. The circuit covering metal shield 106 maysurround several elements of the device including the internal EMI/RFIfilter 108, the ESD protection 110, the supply filtered balanced signalamplifier 112, supply filtered signal filter 114, and supply filteredanalog to digital converter 116. The metal shield 106 may provide aninternal environment shielded against interference. The metal shield 106is connected to a multitude of ¼″ spaced ground connections 104 forproviding a good and solid ground connection even at extremely highfrequencies.

The wire pairs 122 extending from the external EMI/RFI filter maypenetrate the wall of the metal box 106 and may further extend to theinternal EMI/RFI filter. As such, the wire pairs 122 may act as aconduit for interference to enter the protective metal box 106. Thus,the internal EMI/RFI filter 108 may act as a second level of protectionagainst interference and may be directed at filtering conductedemissions and common mode emissions. This filter 108 may be configuredto filter out interference ranging from about 2 KHZ to 500 MHz. Theinternal EMI/RFI filter 108 may be connected to the ESD protection 110via wire pairs 124.

The ESD protection 110 may provide a barrier to electrostatic shock. Bydissipating high levels of energy entering the device, the ESDprotection 110 may protect the device from damage due to such surges ofenergy. The ESD protection 110 may be connected to a supply filteredbalanced signal amplifier 112 with wire pair 126.

The supply filtered balanced signal amplifier 112 may be configured tofilter out any internal interference emitted by internal elements of thedevice. In fact, each of the remaining elements of the EMI/ESD Hardenedsensor interface including the balanced signal amplifier 112, signalfilter 114, and analog to digital conversion may all be configured tofilter out this internal interference further adding to theself-compatibility of the device.

The supply filtered balanced signal amplifier 112 may be furtherconfigured to amplify the incoming signal. The biological signalsreceived from a patient are commonly low energy signals. Having filteredout most of the interference, the signal may be amplified without alsoamplifying associated noise. As such, the signal may be made moreidentifiable and more appropriate for analysis. The supply filteredbalanced signal amplifier 112 may be connected to the supply filteredsignal filter 114 via single wire 128.

It is noted here that wire pairs 3, 120, 122, 124, and 126 may beconfigured, as is well known in the art, to rely on each other to cancelout certain amounts of interference. The current connection 128 may be asingle wire connection because of the internal environment provided bymetal shield 106 and the upstream filters.

The supply filtered signal filter 114 may receive the amplified signalfrom the supply filtered balanced signal amplifier 112 via theconnection 128. As mentioned above, the supply filtered signal filter114 may also be configured to filter out internal interference. Inaddition, the supply filtered signal filter is configured to filter outartifacts of the biological signal. These artifacts may include signalspicked up by the sensor 2 and included in the signal transmitted to thestimulation controller. These artifacts may be an associated heart rateof a patient, other noises or movements in a room, or other signalspicked up by the sensor in addition to the signal intended. Withknowledge of the range of frequencies expected to be received from aparticular sensor, based on the condition being monitored, the supplyfiltered signal filter 114 may filter out those frequencies notpertinent to the analysis. For example, if breathing is being monitored,a range of the expected frequency of breathing can be used to eliminatesignals outside that range. The supply filtered signal filter may beconnected to a supply filtered analog to digital converter via wire 130.

The supply filtered analog to digital converter 116 may be configured,like the balanced signal amplifier 112 and the signal filter 114, tofilter out internal interference. In addition, the analog to digitalconverter 116 may convert the signal from an analog signal to a digitalsignal by converting positive sloping portions of a breathing curve to adigital inhalation signal and by converting negative sloping portions ofa breathing curve to a digital exhalation signal.

It is noted here that connection 130, extending from the signal filter114 to the analog to digital converter 116, may be split so as toprovide an output of the fully filtered analog signal to a diagnosticindicator and PSG interface prior to converting the signal to a digitalsignal. The digital signal then, may be output via connection 112 to thediagnostic indicator and PSG interface and also to additional elementsof a stimulation controller.

Referring to FIG. 3C there is indicated more specifically by numeral 10a detailed schematic diagram of the EMI/ESD hardened sensor Interface.The sensor input connector 101 comprises of connector J1 with thetwo-signal wire pair leads designated as pin 1 and pin 2 respectively.The external EMI/RFI 102 filter comprises of a pair of ferrite beads FB1and FB2 acting as the filter series element, and of a pair of metalshield penetrating feed-through capacitors C1 and C2 as the parallelelement to ground for common mode filtering. The metal shield 106 coversthe sensitive signal carrying analog signal circuit and is connected toa multitude of ¼″ spaced ground connections 104 for providing a very lowimpedance connection to circuit ground even at extremely highfrequencies. The metal shield 106 in connection with the printed circuitground plane on the opposite side of the PCB and with an RF tight picketfence constructed of interleaved vias that connect the ground plane tothe ground flooded top component copper layer forms a continuouselectrostatic shield around the entire volume of the EMI/ESD hardenedsensor Interface 10. The internal EMI/RFI filter 108 comprises adifferential mode filtering capacitor C3 connected to C1 and C2. Alsoconnected to C1 and C2 is the input wire pair of a high frequency commonmode choke L1. The output wire pair of the high frequency common modechoke L1 is connected to the input of the two ESD energy absorbingseries resistors R1 and R2 and to a second filter capacitor C4. Theoutput wire pair of the energy absorbing resistors R1 and R2 isconnected to another set of EMI suppressing filter capacitors C5, C6 andC7. The ESD protection 110 comprises primarily of diodes D1, D2, D3 andD4. The cathode of D1 is connected to the positive supply terminal. Theanode of D1 is connected to the non-inverting input terminal 3 of opampU1. The anode of D2 is connected to the negative supply terminal. Thecathode of D2 is connected to the non-inverting input terminal 3 ofopamp U1. The cathode of D4 is connected to the positive supplyterminal. The anode of D4 is connected to the non-inverting inputterminal 3 of opamp U2. The anode of D3 is connected to the negativesupply terminal. The cathode of D3 is connected to the non-invertinginput terminal 3 of opamp U2. D1 through D4 present the parallelclamping element of the ESD protected opamp input terminal. Resistors R1and R2 in connection with the Diodes D1, D2, D3 and D4 form an ESDsuppression circuit. Resistors R1 and R2 form the series ESD powerabsorbing elements. It is clearly shown that the input terminal 3 nodeof the operational amplifier U1 and U2 of the supply filtered balancedsignal amplifier 112 are thus EMI and ESD protected. The supply filteredbalanced signal amplifiers 112 comprise of operational amplifiers(opamps) U1 and U2. Both opamps U1 and U2 are connected in atwo-amplifier instrumentation amplifier configuration. The four gainsetting resistors RP1: A, RP1: B, RP1: C and RP1: D are closely matched(typically to 0.1%) within the same single resistor package so toprovide the maximum amount of common mode rejection. Resistor R4 bymeans of connection to signal ground provides the input signal load forthe J1.1 signal. Resistor R8 by means of connection to signal groundprovides the input signal load for the J1.2 signal. Negative supplyfiltering of the operational amplifier U1 comprises of a conducted RFpower absorbing inductor L2 and a conducted RF power suppressingcascaded capacitor bank consisting of C8 and C10 in parallel to ground.The conducted RF power absorbing inductor L2 is connected in series withthe negative supply power terminal V− and the negative power supplyterminal 2 of the operational amplifier U1. Positive supply filtering ofthe operational amplifier U1 comprises of a conducted RF power absorbinginductor L3 and a conducted RF power suppressing cascaded capacitor bankconsisting of C9 and C12 in parallel to ground. The conducted RF powerabsorbing inductor L3 is connected in series with the positive supplypower terminal V+ and the positive power supply terminal 5 of theoperational amplifier U1. Furthermore, conducted emissions bypassingcapacitor C11 is connected across the U1 operational amplifier power pin2 and pin 5. Negative supply filtering of the operational amplifier U2comprises of a conducted RF power absorbing inductor L4 and a conductedRF power suppressing cascaded capacitor bank consisting of C13 and C15in parallel to ground. The conducted RF power absorbing inductor L4 isconnected in series with the negative supply power terminal V− and thenegative power supply terminal 2 of the operational amplifier U2.Positive supply filtering of the operational amplifier U2 comprises of aconducted RF power absorbing inductor L5 and a conducted RF powersuppressing cascaded capacitor bank consisting of C14 and C17 inparallel to ground. The conducted RF power absorbing inductor L5 isconnected in series with the positive supply power terminal V+ and thepositive power supply terminal 5 of the operational amplifier U2.Furthermore, conducted emissions bypassing capacitor C16 is connectedacross the U2 operational amplifier power pin 2 and pin 5. The singleended output of the supply filtered balanced signal amplifier 112 isavailable at the pin 1 of operational amplifier U2. The output of thesupply filtered balanced signal amplifier 112 connects to the input ofthe supply filtered signal filter 114. The supply filtered signal filter114 is configured as a 3^(rd) order Butterworth low pass filter by meansof filter series element resistors R10, R11 and R12 and by means offilter parallel elements C18, C19 and C20. Negative supply filtering ofthe operational amplifier U3 comprises of a conducted RF power absorbinginductor L6 and a conducted RF power suppressing cascaded capacitor bankconsisting of C21 and C23 in parallel to ground. The conducted RF powerabsorbing inductor L6 is connected in series with the negative supplypower terminal V− and the negative power supply terminal 2 of theoperational amplifier U3. Positive supply filtering of the operationalamplifier U3 comprises of a conducted RF power absorbing inductor L7 anda conducted RF power suppressing cascaded capacitor bank consisting ofC22 and C25 in parallel to ground. The conducted RF power absorbinginductor L7 is connected in series with the positive supply powerterminal V+ and the positive power supply terminal 5 of the operationalamplifier U3. Furthermore, conducted emissions bypassing capacitor C24is connected across the U3 operational amplifier power pin 2 and pin 5.The single ended output of the supply filtered signal filter 114 isavailable at the pin 1 of operational amplifier U3. The output of thesupply filtered signal filter 114 connects to the input of the supplyfiltered analog to digital converter 116. The supply filtered analog todigital converter 116 is configured as a self-referencing phase detectorby means of phase shifting series element resistors R13 and by means ofphase shifting parallel element C26 feeding into the inverting andnon-inverting inputs of opamp U4. The signal detection threshold of theself-referencing phase detector is set by the ratio of resistor R15 toR14. A ratio of 0.01 has been found to be working optimally in thisapplication. Negative supply filtering of the operational amplifier U4comprises of a conducted RF power absorbing inductor L8 and a conductedRF power suppressing cascaded capacitor bank consisting of C27 and C29in parallel to ground. The conducted RF power absorbing inductor L8 isconnected in series with the negative supply power terminal V− and thenegative power supply terminal 2 of the operational amplifier U4.Positive supply filtering of the operational amplifier U4 comprises of aconducted RF power absorbing inductor L9 and a conducted RF powersuppressing cascaded capacitor bank consisting of C28 and C31 inparallel to ground. The conducted RF power absorbing inductor L9 isconnected in series with the positive supply power terminal V+ and thepositive power supply terminal 5 of the operational amplifier U4.Furthermore, conducted emissions bypassing capacitor C30 is connectedacross the U4 operational amplifier power pin 2 and pin 5. The singleended output of the supply filtered analog to digital converter 116 isavailable at the pin 1 of operational amplifier U4. The single endedoutput 12 of the supply-filtered analog to digital converter 116connects to the input of the Activity Detector 20.

Referring to FIG. 3D, there is indicated a timing diagram of the analogto digital conversion function of the EMI/ESD hardened Sensor Interface10. The top graph indicated by roman numeral I. depicts the analogwaveform representation of the respiratory signal coming from theairflow sensor. The bottom graph indicated by Roman numeral II. Depictsthe digital representation of the respiratory signal to the ActivityDetector. A positive slope of the analog waveform represents inhaling. Anegative slope of the analog waveform represents exhaling. The output ofthe supply filtered analog to digital converter 116 of FIG. 25 changesits output to a low level as soon as the analog waveform of graph I.changes its slope from positive to negative indicating exhaling. Theoutput waveform of the supply filtered analog to digital converter 116in graph II. changes its output to a high level as soon as the analogwaveform of graph I. changes its slope from negative to positiveindicating inhaling.

Due to the nature of the device application, through its typical longsensor and transducer wires, exposure of the output to ESD maypotentially destroy the transducer driver circuitry. Thus, special ESDcountermeasures have to be put in place in order to prevent damage ortotal destruction of the sensitive, low power circuitry.

The EMI/ESD hardened sensor interface 10 may comprise a multitude ofEMI/ESD countermeasures in order to ensure that the sensor signal 3 willbe detected, processed and decoded correctly by this invention withoutsuffering from the adverse affects of EMI and ESD. The following is alist of EMC component level countermeasures for the EMI/ESD hardenedsensor interface:

The following is a list of EMC component level countermeasures for theEMI/ESD hardened sensor Interface:

1. Feed-through capacitors

2. Instrumentation amplifier

3. Matched gain setting resistor network to maintaining high CMRR

4. Ferrite beads, series EMI suppression element

5. Filter capacitors, parallel EMI suppression element

6. Common mode RF filter, parallel EMI suppression element

7. Common mode RF choke, series EMI suppression element

8. Power supply rail filtering

9. Signal decoupling, parallel EMI suppression element

10. Signal lead filtering, series EMI suppression element

11. Component location

12. PCB routing

13. Close proximity

14. Short and wide traces are better than long and skinny ones

15. Schottky diodes, EMI suppression parallel element

16. Resistors, series EMI suppression element

17. Inductors, series EMI suppression element

18. Cascaded capacitor banks, 0.01 uf and 10 uF

19. Inductors in V+ and V− feeds before capacitor cascade, power feedoutput

For the purpose of EMI/RFI shielding of the EMI/ESD hardened sensorInterface 10, a metal case is mounted on to of the picket fenced PCBcircuit boundary with ground pane and ground flooded signal layers.

The use of the following PCB based EMC countermeasures:

1. Power and ground planes

2. Layer flooding

3. Picket fencing

4. Short and narrow signal traces

5. Short and wide power traces

The following operational parameters are adjustable

1. Filter response (Butterworth, Bessel, Chebyshev, Elliptic, etc.)

2. High pass cut-off frequency (0.01 Hz to 100.00 Hz)

3. Low pass cut-off frequency (0.01 Hz to 100.00 Hz)

4. Signal Amplifier gain (−70 dB to +40 dB)

5. Signal detection threshold (0.01% to 10%)

EMI/ESD hardening against the aforementioned offenders not onlysatisfies domestic and international requirements on emissions andsusceptibility but also results in robust operation, cleaner internalsignals, improved signal to noise ratio (SNR) and greater dynamic range.The sensor interface 10 described herein allows for a stimulationcontroller to be used with various sensors including those to bedeveloped in the future. Moreover, the sensor interface described allowsfor a practitioner to view an analog and digital version of a patientsignal and further allows for additional analysis and processing of eachsignal.

A method of using the sensor interface may involve positioning a sensoron a patient and connecting the sensor to the sensor interface. Themethod may further involve receiving a signal from the sensor positionedon the patient and filtering the signal to remove EMI/RFI interference,further treating the signal to prevent transmission of ESD, filteringout internal interference, amplifying the signal, further filtering thesignal to remove signal artifacts resulting from the sensor sensitivity,converting the signal from an analog to a digital signal and outputtingeither an analog signal, a digital signal, or both.

Activity Detector

An activity detector may receive a previously converted digital signalfrom a sensor interface as shown in FIGS. 2A and 2B. The received signalmay, for example, indicate when a person is inhaling and when they areexhaling. The activity detector may interpret that signal based oncertain stored information. For example, the activity detector may becalibrated based on a patient's status as an adult and may define anupper limit of one inhalation/exhalation cycle as being 6 seconds long.By monitoring the incoming digital inhalation/exhalation signal theactivity detector may determine if a cycle is abnormal. The activitydetector may then notify other elements of a stimulation controller.

There is a need for a device that can monitor a patient for basicindications of a sleep disorder to allow other portions of an apparatusto standby on less than full power unless and until they are needed.

Referring to FIG. 4A, there is indicated more specifically by numeral 20an Activity Detector. AN ACTIVITY IS NOT LIMITED TO APNEA IT MAY ANYEVENT SUCH AS SNORING, LEG MOVEMENT, LIMB MOVEMENT, JAW MOVEMENT,POTENTIAL SIDS EVENT (BABY NOT BREATHING), ETC. The Activity Detector 20receives its input via the digital signal 12 from the output of theEMI/ESD hardened sensor Interface 10. The Activity Detector 20 connectsvia the activity signal 22 to the Stimulus Timer 30. For the purpose ofinter-device communication, command and control, the Activity Detector20 connects to the Device Controller Bus 92. A detailed description ofthe Activity Detector 20 is provided below and in a separately filedU.S. Provisional Patent Application titled Activity Detector for aclosed loop neuromodulator, filed on Aug. 22, 2008, the contents ofwhich are hereby incorporated by reference herein.

The decision of whether a patient is experiencing an apnea or isbreathing normally is made in the Activity Detector.

An activity detector 20 is shown receiving a digital airflow signal 12from an EMI/ESD hardened sensor interface 10. The Activity Detector 20may transmit an activity signal 22 to a stimulus timer or other elementsof a stimulation controller. Additionally, for purposes of inter-devicecommunication, command, and control, the activity detector 20 may alsobe connected to a device controller bus 92. Also shown in FIG. 4A is adiagram of inhalation and exhalation as it relates to normal andabnormal breathing. It is noted here, that an activity can be anyactivity relevant to a neurological condition. In many cases, as in thecase of sleep apnea, the relevant activity will be breathing activity.For purposes of discussion, a majority of following relates toinhalation and exhalation as it relates to sleep apnea, but thoseskilled in the art will understand and appreciate that the activitycould also be snoring, leg movement, limb movement, jaw movement, or anyother activity relevant to a neurological condition or sleep disorder.

The Activity Detector 20 may convert the digital airflow signal 12, orother relevant signal, into a digital activity signal 22. As shown inFIG. 4A, the digital airflow signal 12 is high when the patient isinhaling and is low when the patient is exhaling. In contrast, thedigital activity signal 22 is high when the patient is breathingnormally and is low when the patient is breathing abnormally. Theactivity detector 22 may determine the difference between normal andabnormal based on previously set or calibrated standards. For example,the typical breathing range for a sleep patient may be between 10 to 20breaths per minute reflecting a 3 to 6 second breathing cycle. Thus, theactivity detector may be calibrated to indicate abnormal breathing whenthe patient fails to breath for more than 6 seconds. The availablerange, however, can be set to any range relevant to the activity beingmonitored and may even be calibrated to detect continuity of activityrather than absence of activity. For example, leg movement disorders mayinvolve setting the activity detector to trigger the remaining elementsof the stimulation controller when the activity continues for a givenamount of time.

The Activity Detector 20 converts the digital airflow signal 12 into adigital activity signal 22. The digital airflow signal 12 is high whenthe patient is inhaling and is low when the patient is exhaling. Thedigital activity signal 22 is high when the patient is breathingnormally and is low when the patient is breathing not normally. Thetypical breathing range for a sleep patient is between 10 to 20 breathsper minute. The invention goes well above and below this rate toaccommodate other events in other CNS disorders.

A purpose of the Activity Detector 20 is to detect obstructive sleepapnea, central sleep apnea, complex sleep apnea, but also snore, snoreand apneas, leg movement, limb movement, jaw movement etc.

Referring to FIG. 4B, there is indicated more specifically by numeral 20a detailed block diagram of the Activity Detector. The activity detectormay include several inhalation and exhalation devices including: gates204, 206, counters 220, 224, registers 216, 228, magnitude comparators246, 238, and count threshold registers 230, 240. The activity detectormay also include a respiration sampling clock and a respiration samplingclock register as well as an activity gate 244.

The inhalation and exhalation gates 204, 206 may continually receive theincoming digital airflow signal 12 and send timed signals to theirrespective counters 220, 224. For example, when the incoming digitalairflow signal 12 is high, reflecting inhalation, the inhalation gate204 may send a signal to the inhalation counter 220 every millisecond orany other regular time interval. This regular time interval may bereferred to as the clock sampling rate and the gates 220, 224 may relyon the respiration sampling clock 202 to trigger them based on thissampling rate. Thus, based on the information the gates 204, 206 receivefrom the incoming digital airflow signal 12 and the respiration samplingclock 202, the gates 204, 206 may “open” and thus send a triggeringsignal to their respective counters 220, 224. In turn, each time theinhalation and exhalation counters 220, 224 receive a signal from theirrespective gate 204, 206, the counters 220, 224 may advance their count.

Signal 12 actually gates the sampling clock and allows a specific amountof clock pulses to reach the counter in order to give a signal countthat is relative to the inhalation or exhalation duration. If that countis higher than the threshold then abnormal breathing has been detected.

The respiration-sampling clock 202, responsible for triggering theinhalation and exhalation gates 204, 206 based on the clock samplingrate, may receive this clock sampling rate through an 8-bit parallelload port connection to a respiration sampling clock register 208. Therespiration sampling clock register 208 may be interfaced with aninternal control bus 92. The register is readable and writable and theclock sampling rate can be stored in the respiration clock register 208via the control bus 92 and may be adjusted as required for a givencondition. The respiration sampling clock 202, may then receive thisclock sampling rate from the register 208 and trigger the gatesaccordingly.

Referring again to the inhalation and exhalation counters 220, 224, aprimary 8-bit parallel output 234, 236 of the counters may be connectedto the 8-bit input of their respective magnitude comparators 246, 238.The magnitude comparators 246, 238 may constantly compare the actualinhalation or exhalation count to a threshold count. As soon as theactual inhalation or exhalation count of the respective counter is equalto or greater than a respective threshold count, the magnitudecomparator may issue a single bit magnitude signal 242, 248 to theactivity gate 244.

Similar to the respiration sampling clock, the magnitude comparators246, 238 rely on a count threshold register 230, 240 interfaced with acontrol bus 92. The count threshold registers 230, 240 are readable andwritable and the threshold value may be stored in the registers via thecontrol bus 92. This value may then be uploaded to the magnitudecomparators 246, 238 via the 8-bit parallel connection 234, 236, forcomparison with the actual count. For example, if a 6 second breathingcycle is considered normal and anything over 6 is abnormal, theinhalation threshold and exhalation threshold may each be set toapproximately 3 seconds in the count threshold registers 230, 240. Thisvalue can then be uploaded by the magnitude comparators 246, 238 andcompared with the actual count of a patient.

The actual inhalation/exhalation count established by the counters 220,224 may also be available via a byte wide secondary count paralleloutput 218, 226 extending to an 8-bit count register 216, 228. As withthe respiration sampling clock register, the inhalation and exhalationcount registers may be interfaced with an internal control bus 92. Assuch, the actual 8-bit inhalation or exhalation count may be read viathe count registers 216, 228 through the 8-bit internal control bus 92.

Referring back to the activity gate 244, it may provide an activitysignal 22 to additional elements of a stimulation controller. Theactivity signal 22 may be high during normal breathing and low duringabnormal breathing. When either the inhalation magnitude comparator 246or the exhalation magnitude comparator 238 provides a low signal, due toan inhalation or exhalation counter overrun, the activity signal 22 mayalso provide a low signal, indicating abnormal breathing. It is notedthat the activity signal 22 may not reflect an Apnea event because inorder for the detected non-breathing event to be qualified as a sleepapnea, the breathing has to secede for a medically established amount oftime. Further analysis may be provided within a stimulus timer todetermine whether an apnea event has been detected.

A method of providing a normal or abnormal activity signal includesreceiving a digital inhalation and exhalation signal, counting the timefor each of inhalation and exhalation and comparing the count to athreshold value. The method further includes providing a normal activitysignal when the threshold value is not exceeded and providing anabnormal activity signal when the threshold value is exceeded.

Respiration sampling clock range: 0 to 255 ms, 1 ms resolution

Inhalation count register range: 0 to 255 s, 1 s resolution

Exhalation count register range: 0 to 255 s, 1 s resolution

Inhalation count threshold range: 0 to 255 s, 1 s resolution

Exhalation count threshold range: 0 to 255 s, 1 s resolution

An advantage of the present subject matter is that the information itprovides allows for the device to make further decisions on how much ofthe device needs to be activated. For instance, if breathing iscontinually normal, the device may temporarily shut down other elementsto conserve energy. (E.g. shut down generators, timers and gain blockwhen breathing is detected. Activate generators, timers and gain blockwhen no breathing is detected.)

Referring to FIG. 4B, there is indicated more specifically by numeral 20a detailed block diagram of the Activity Detector. Input connection tothe output of the EMI/ESD Hardened Sensor Interface is provided by thedigital signal 12. The digital input 12 connects to the first input ofthe inhalation gate 204 and to the first input of the exhalation gate206. The respiration-sampling clock 202 connects to the second input ofthe inhalation gate 204 via connection 212. The respiration-samplingclock 202 also connects to the second input of the exhalation gate viaconnection 212. The clock-sampling rate of the respiration-samplingclock 202 is being set by the loading of the respiration-sampling clock202 via its 8-bit parallel load port 210 via the respiration samplingclock register 208. The respiration sampling clock register can bewritten and read-back via the inhalation count register 216 through the8-bit internal control bus 92. The output of the inhalation gate 204provides a gated/timed inhalation clock signal via its output 222 to theinput of the inhalation counter 220. The inhalation counter 220 advancesits count each time a gated inhalation clock signal triggers it. Theactual inhalation count is available via the byte wide secondaryinhalation count parallel output 218. An 8-bit inhalation count register216 is connected to the inhalation count output 218. The actual 8-bitinhalation count can be read via the inhalation count register 216through the 8-bit internal control bus 92. The primary 8-bit paralleloutput 234 of the inhalation counter 220 is connected to the 8-bit inputof the inhalation magnitude comparator 246. The 8-bit inhalationmagnitude comparator 246 constantly compares the actual inhalation countvia the 8-bit parallel connection 234 from the inhalation counter 220with the inhalation threshold count port 232 whose value has been loadedinto the inhalation count threshold register 230 via the internalcontrol bus 92. As soon as the actual inhalation count of inhalationcounter is equal or greater than the inhalation threshold count that hasbeen loaded into the inhalation count threshold register 230, a singlebit magnitude signal 242 is being issued and passed to the two input ORgate 244. The output of the exhalation gate 206 provides a gated/timedexhalation clock signal via its output 214 to the input of theexhalation counter 224. The exhalation counter 224 advances its counteach time a gated exhalation clock signal triggers it. The actualexhalation count is available via the byte-wide secondary exhalationcount parallel output 226. An 8-bit exhalation count register 228 isconnected to the exhalation count output 226. The actual 8-bitexhalation count can be read via the exhalation count register 228through the 8-bit internal control bus 92. The primary 8-bit paralleloutput 226 of the exhalation counter 224 is connected to the 8-bit inputof the exhalation magnitude comparator 238. The 8-bit exhalationmagnitude comparator 238 constantly compares the actual exhalation countvia the 8-bit parallel connection 236 from the exhalation counter 224with the exhalation threshold count port 250 whose value has been loadedinto the exhalation count threshold register 240 via the internalcontrol bus 92. As soon as the actual inhalation count of the exhalationcounter 224 is equal or greater than the exhalation threshold count thathas been loaded into the exhalation count threshold register 240, asingle bit magnitude signal 246 is being issued and passed to the twoinput OR gate 244. The output of the Two Input OR gate 244 is highduring normal breathing. As soon as either the inhalation magnitudecomparator or the exhalation comparator goes low due to an inhalation orexhalation counter overrun do to a non breathing event, the ActivitySignal output 22 of the two input OR gate 244 goes low, indicatingabnormal breathing. The activity signal 22 is not an Apnea signalbecause in order for the detected non-breathing event to be qualified asa sleep apnea, the breathing has to secede for at least a few seconds.The decision whether an apnea event has been detected is made within theStimulus Timer 30.

FIG. 4C is a timing diagram of an apnea detection of an ActivityDetector according to one example of the present subject matter.

In one embodiment, an activity detector is provided including arespiration sampling clock, at least one gate, at least one counter, atleast one magnitude comparator, and an activity gate. In thisembodiment, the respiration sampling clock is configured to provide aclock sampling rate to the at least one gate. The at least one gate isconfigured to receive a digital inhalation and exhalation signal andtrigger the at least one counter based on the clock sampling rate. Theat least one magnitude comparator is configured to compare a countprovided by the at least one counter to a threshold count and signal theactivity gate, when the threshold count is exceeded. In this embodiment,the activity gate is configured to provide an activity signal indicatingnormal or abnormal breathing.

In another embodiment, the at least one gate includes an inhalation gateand an exhalation gate. In another embodiment, the at least one counterincludes an inhalation counter and an exhalation counter. In anotherembodiment, the at least one magnitude comparator includes an inhalationmagnitude comparator and an exhalation magnitude comparator. In yetanother embodiment, each of the respiration sampling clock, the at leastone gate, the at least one counter, and the at least one magnitudecomparator each have an associated register for communication with acontrol bus.

In another embodiment, a method of providing a normal or abnormalactivity signal includes receiving a digital inhalation and exhalationsignal, counting the time for each of inhalation and exhalation andcomparing each count to a separate threshold value. The method furtherincludes providing a normal activity signal when the threshold value isnot exceeded and providing an abnormal activity signal when thethreshold value is exceeded.

Stimulus Timer

A stimulus timer may receive a previously converted digital signal froman activity detector as shown in FIGS. 2A and 2B. As shown in FIG. 3,the received signal may, for example, indicate when a person isbreathing abnormally. The stimulus timer may further analyze the signalto determine if any abnormal activity constitutes a manifestation of asleep disorder. For example, the stimulus timer may be set to triggeradditional elements of a closed loop neuromodulator when a person failsto breath for more than 20 seconds. Thus, by monitoring the incomingdigital activity signal the stimulus timer may determine if the abnormalbreathing constitutes sleep apnea and may notify other elements of astimulation controller accordingly. The stimulus timer may provide astimulus start signal, a stimulus rate signal, and a stimulus durationsignal.

Referring to FIG. 5A, a stimulus timer 30 is shown receiving an incomingactivity signal 22 from an activity detector 20. The stimulus timer 30may transmit a stimulus start signal 32, a stimulus rate signal 34, andstimulus duration signal 36 to a stimulus sequencer 40 or other elementsof a stimulation controller. Additionally, for purposes of inter-devicecommunication, command, and control, the stimulus timer 30 may also beconnected to a device controller bus 92.

Referring to FIG. 5A, there is indicated more specifically by numeral 30a stimulus timer. The stimulus timer 30 receives its input via theactivity signal 22 from the Activity Detector 20. The stimulus timer 30connects via the stimuli start signal 32, stimuli rate signal 34 and thestimuli duration signal 36 to the stimulus sequencer 40. For the purposeof inter-device communication command and control, the Stimulus Timer 30connects to the common Device Controller Bus 92. A detailed descriptionof the stimulus timer 30 is provided below and in a separately filedU.S. Provisional Patent Application titled Stimulus Timer for a closedloop neuromodulator, filed on Aug. 22, 2008, the contents of which arehereby incorporated by reference herein.

The Stimulus Timer is responsible for diagnostic and therapy relatedclosed loop neuromodulator functions.

A purpose of the Stimulus Timer 30 is to process the activity signal 22from the Activity Detector 20 and derive specific timing informationfrom it that is crucial to the operation of the closed loopneuromodulator such as therapy delay, apnea detection, apnea durationmeasurement, apnea counts, stimulus delay, stimulus rate and stimulusduration timing.

In addition, the Stimulus Timer 30 enables, a low power design, which iscrucial for battery operation. A genera power down signal that will beissued to all functional but non essential elements can be issued by thedevice controller by polling the apnea duration register. The generalpower down signal will keep other functional modules and functionalblocks of the design inactive until their function and operation areneeded, milliseconds after an apnea has been detected. Low poweroperation shuts down functional blocks when not needed for immediateoperation. E.g. shut down generators, timers and gain block whenbreathing is detected. Activate generators, timers and gain block whenno apnea has been detected.

The timing of issuing stimuli and sending them to the patient continuesuntil the resumption of breathing has been detected.

Referring to FIG. 5B, a detailed block diagram of the stimulus timer 30is provided. The stimulus timer 30 may include several therapy delayelements including a gate 310, timer 306, and register 302. The stimulustimer 30 may also include several apnea threshold elements including agate 322, timer 318, and register 314. Additional apnea related devicesinclude an apnea duration timer 330 and an apnea duration register 326as well as an apnea counter 338 and an apnea count register 334. It isnoted here, that the neurological condition or sleep disorder is notlimited to sleep apnea, but that reference is made to sleep apnea forpurposes of description. Those skilled in the art will understand andappreciate that the sleep disorder could also be snoring, bruxism, orany other neurological condition or sleep disorder. Several stimulirelated elements may also be included. A stimulus delay gate 348, timer344, and register 340 may be provided as well as a stimulus rategenerator 354 and register 350. Additional stimulus related elements mayinclude a stimulus duration timer 362 and register 358 as well as astimulus counter 366 and stimulus count register 312.

As previously discussed, the stimulus timer 30 may receive an activitysignal 22 from an activity detector 20. The activity signal 22 may bedirected into a first input of a therapy delay gate 310. Together withthe therapy delay timer 306 and therapy delay register 302, the therapydelay gate 310 may allow a stimulation controller to be set not toprovide any stimulus for a given period of time. For example, if it isdesired to allow a patient to achieve a certain sleep state or simplyget into a reasonably deep sleep prior to stimulating them, the therapydelay system can be set to block stimulation until a certain time haspassed. As such, the therapy delay register 302, which is both writableand readable through the 8-bit internal control bus 92, allows for adelay to be stored in the therapy delay register 302. The therapy delaytimer 306 receives its therapy delay time value through the 8-bitparallel connection 304 to the Therapy delay register 302 and, in turn,may signal the therapy delay gate 310 to open once the time has elapsed.

Once the therapy delay time has elapsed, the therapy delay gate 310allows the activity signal to pass through to the apnea threshold gate322 via connection 324. The apnea threshold gate 322 in conjunction withthe apnea threshold timer 318 and apnea threshold register 314 qualifieswhether the patient experiences an apnea or not. That is, the length oftime defining sleep apnea (e.g. 20 seconds), or any other condition, canbe stored in the apnea threshold register 314, which can be written toand read-back through the 8-bit internal control bus 92. The apneathreshold timer 318 receives its apnea threshold value through the 8-bitparallel connection 316 to the apnea threshold register 314 and, inturn, may signal the apnea threshold gate 322 to open once the apneathreshold has been exceeded. That is, when the activity signal hasremained low for longer than the apnea threshold, the apnea thresholdgate 322 will open.

The apnea threshold gate 322 connects to the stimulus delay gate 348 viaconnection 324. Along its path to the stimulus delay gate 348, theconnection 324 also connects to the apnea duration timer 330 and theapnea counter 338. The apnea duration timer 330 may measure the apneaduration indicated by a low level of Therapy delay [[apnea threshold]]gate output 324 [[332]]. The apnea counter may count individual apneasas indicated by the output of the apnea threshold gate 322. Theseelements are intended for collecting data for export via the internalcontrol bus 92. Thus, these elements are further connected via 8-bitparallel connections to associated registers 326 and 334. The apneaduration register 326 and apnea count register 334 are, in turn,connected via an 8-bit connection to the internal control bus 92. Aswith other registers disclosed herein, these registers 326, 324 arereadable and writable so as to be able to store the values associatedwith the apnea duration timer and apnea counter for later reading byanother device.

Beyond the apnea duration timer 330 and the apnea counter 338, theconnection 324 proceeds to the stimulus delay gate 348. The stimulusdelay gate 348 delays the start of any CNS stimulus until the setStimulus Delay Time has expired. This stimulus delay may allow for anadditional level of control over the timing of the stimulus. That is,the stimulus may be delayed due to the therapy delay. It may also bedelayed beyond a determination of abnormal breathing to wait for adetermination of whether an apnea has occurred. While the stimulus delaymay be set to zero, it may also be set to some positive value providingsome level of control over the timing of the stimulus relative to adetermination of apnea. Thus, the stimulus may not be deliveredimmediately once an apnea has been determined. Similar to the previouslydiscussed register, timer, and gate combinations, a stimulus delayregister 340 may be provided to store the stimulus delay time. Thestimulus delay register 340 may be both readable and writable via an 8bit internal control bus 92. The stimulus delay timer may receive thestimulus delay time through the 8-bit parallel connection 342 from thestimulus delay register 340. The stimulus delay timer 344 connects tothe stimulus delay gate 348 and may allow the stimulus delay gate 348 toopen once the stimulus delay time has elapsed.

The stimulus delay gate 348 connects to the stimulus rate generator 354via connection 32. Connection 32 represents the stimulus start signal.If the therapy delay time has elapsed and the apnea threshold time hasbeen exceeded and the stimulus delay time has elapsed, a stimulus startsignal may be released from the stimulus delay gate 348 throughconnection 32.

This stimulus start signal may be directed out of the stimulus timer,but also is directed to the stimulus rate generator 354 for furtherprocessing. The stimulus rate generator 354 generates the stimulationrate at which the CNS stimuli are sent to the transducer/patient. Thatis, where successive stimuli are being used to treat a patient, thestimulus rate generator 354 defines the time from the start of onestimulus to the start of the next stimulus. The stimulus rate generator354 may receive its input directly from the stimulus rate register 350through the 8-bit parallel connection 352. As with other registers, thestimulus rate register 350 is responsible for storing the stimulus rate.The stimulus rate register 350 may be both writable and readable throughthe 8-bit internal control bus 92.

The stimulus rate generator 354 connects to the stimulus duration timer362 via connection 34. Connection 34 represents the stimulus ratesignal. This stimulus rate signal may be directed out of the stimulustimer 30, but may also be directed to a stimulus duration timer 362 forfurther processing. The stimulus duration timer 362 may define the timeover which the CNS stimuli are sent to the transducer/patient. That is,where single or multiple stimuli are being used to treat a patient, thestimulus duration timer defines the continuous length of each individualpulse. Like the stimulus rate generator/register combination, thestimulus duration timer 362 receives its duration time value through the8-bit parallel connection 360 to the stimulus duration register 358. Thestimulus duration register 358 can be written to and read-back throughthe 8-bit internal control bus 92. The output of the stimulus durationtimer 362 is the stimulus duration signal 36.

The timing of issuing stimuli and sending them to the patient may becontinued until the resumption of breathing has been detected. As thisprocess continues, the stimulus counter 366 may keep track of the numberof stimuli being issued. The stimulus counter 366, may in turn storethis value in the readable and writable stimulus count register 312,making this value available to the rest of the system through 8-bitinternal control bus 92.

A method may be performed involving receiving an activity signal from anactivity detector, intercepting the activity signal with a therapy delaygate until the therapy delay has lapsed after which the signal passes toa apnea threshold gate. The apnea threshold gate intercepts the activitysignal until an apnea threshold has been exceeded after which the signalpasses to the stimulus delay gate. The stimulus delay gate interceptsthe signal until a stimulus delay has lapsed after which the signal isissued from the stimulus timer as a stimulus start signal. A stimulusrate generator may issue a stimulus rate signal and a stimulus durationtimer may issue a stimulus duration signal.

Therapy delay range: 0 to 255 min, 1 min resolution

Apnea threshold range: 0 to 255 s, 1 s resolution

Apnea duration range: 0 to 255 s, 1 s resolution

Apnea counter range: 0 to 255 apneas

Stimulus delay range: 0 to 25.5 s, 100 ms resolution

Stimuli rate generator range: 0 to 25.5 seconds, 100 ms resolution

Stimuli duration timer range: 0 to 2.55 seconds, 10 ms resolution

Referring to FIG. 5B, there is indicated more specifically by numeral 30a detailed block diagram of the stimulus timer. The input of theStimulus Timer 30 connects to the output of the Activity Detector 20 viathe activity signal 22. The activity signal 22 connects to the firstinput of the therapy delay gate 310. The Therapy Delay Gate 310 delaysany stimulation activity until the set Therapy Delay Time has beenexpired. The Therapy Delay Gate 310 connects to the Apnea Threshold Gate324 via connection 324. The therapy delay timer 306 connects to thesecond input of the therapy delay gate 310 via the connection 308. Thetherapy delay timer 306 receives its therapy delay time value fromthrough the 8-bit parallel connection 304 from the Therapy delayregister 302. The therapy delay register 302 can be written andread-back through the 8-bit internal control bus 92. The Apnea ThresholdGate 322 in conjunction with the Apnea Threshold Timer 318 qualifieswhether the patient experiences an Apnea or not. The apnea thresholdgate 322 connects to the Stimulus Delay Gate 348 via connection 324. TheApnea threshold timer 318 connects to the second input of the ApneaThreshold Gate 322 via the connection 320. The Apnea threshold timer 318receives its apnea threshold value through the 8-bit parallel connection316 from the apnea Threshold Register 314. The apnea threshold Register314 can be written and read-back through the 8-bit internal control bus92. The Apnea duration timer 330 measures the apnea duration indicatedby a low level of Therapy delay gate output 324. The Apnea durationtimer 330 connects to the output 332 of the apnea threshold Gate 322.The value of the Apnea duration timer 330 can be read through the 8-bitparallel connection 328 from the apnea duration Register 326. The apneaduration Register 326 can be read through the 8-bit internal control bus92. The Apnea counter 338 counts individual apneas as indicated by theoutput of the apnea threshold gate 322. The value of the Apnea counter338 can be read through the 8-bit parallel connection 336 from the apneacount Register 334. The apnea count register 334 can be read through the8-bit internal control bus 92. The stimulus delay gate 348 delays thestart of any stimulus until the set Stimulus Delay Time has beenexpired. The stimulus delay Gate 348 connects to the clock input of thestimulus rate generator 354 via connection 32. The stimulus delay timer344 connects to the second input of the stimulus delay gate 348 via theconnection 346. The stimulus delay timer 344 receives its stimulus delaytime value through the 8-bit parallel connection 342 from the stimulusdelay register 340. The stimulus delay register 340 can be written andread-back through the 8-bit internal control bus 92. The stimulus delaygate 348 connects to the stimulus rate generator 354 via connection 32.Connection 32 represents the stimulus start signal. The stimulus rategenerator 354 generates the stimulation rate at which the stimuli aresent to the transducer/patient. The stimulus rate generator 354 connectsto the clock input of the stimulus rate generator 354 via connection 32.The stimulus rate generator 354 receives its stimulus rate value throughthe 8-bit parallel connection 352 from the stimulus rate register 350.The stimulus rate register 350 can be written and read-back through the8-bit internal control bus 92. The stimulus rate generator 354 connectsto the stimulus duration timer 362 via connection 34. Connection 34represents the stimulus rate signal. The stimulus duration timer 362times the stimulation duration at which the stimuli are sent to thetransducer/patient. The input of the stimulus duration timer 362connects to the output of the stimulus rate generator 354 via connection34. The stimulus duration timer 362 receives its duration time valuethrough the 8-bit parallel connection 360 from the stimulus durationregister 358. The stimulus duration register 358 can be written andread-back through the 8-bit internal control bus 92. The output of thestimulus duration timer 362 is the stimulus duration signal 36. Stimulusduration 36 represents the duration at which the patient/transducer issubjected to the current single stimulus.

The single stimulus energy is contained under the area of the individualstimuli pulse shape over time. In order to increase the stimulus energyeither the level of the stimulus must be increased or the duration ofthe stimulus must be increased. The energy provided by any given pulseof stimulation may be determined by defining the area of the individualstimuli pulse shape over time. That is, energy equals power times time(E=P*t) where P represents the power of a stimulus pulse and trepresents the duration of stimulus pulse. In order to increase thestimulus energy either the level of the stimulus can be increased or theduration of the stimulus can be increased. Where sleep practitioners areattempting to stifle a sleep disorder and yet avoid arousing a patient,the ability to adjust each of these is advantageous. The stimulus timerdisclosed herein allows for adjustment for the duration of element ofthis energy approach.

The stimulus timer disclosed herein is advantageous because it allowsfor precise dosing of patients. First, once an apnea or otherneurological condition is detected, the initial dose can be introducedat a specific predetermined time. Second, a series of pulses ofstimulation may be provided and the stimulus timer allows those pulsesto be adjusted relative to one another in time. Third, the stimulustimer further allows for each pulse to be shortened or lengthened.

Additionally, the Stimulus Timer 30 enables, a low power design, whichmay be beneficial under battery operation. When used in a closed loopneuromodulator such as that shown in FIG. 2A or 2B, a general power downsignal may be issued to all functional but non essential elements by thedevice controller, which may poll the apnea duration register todetermine if an apnea is occurring. The general power down signal maykeep other functional modules and functional blocks of the deviceinactive until their function and operation are needed, millisecondsafter an apnea has been detected. Low power operation may allow forshutting down functional blocks when not needed for immediate operation.E.g. shutting down generators, timers and gain blocks when breathing isdetected. Activate generators, timers and gain block when an apnea hasbeen detected.

In one embodiment, a stimulus timer for a closed loop neuromodulatorincludes a therapy delay gate, an apnea threshold gate, a stimulus delaygate, a stimulus rate generator, and a stimulus duration timer, whereinthe stimulus delay gate issues a stimulus start signal, the stimulusrate generator issues a stimulus rate signal, and the stimulus durationtimer issues a stimulus duration signal.

In another embodiment, the stimulus timer also includes an apneaduration timer. In another embodiment, an apnea counter is alsoincluded. In yet another embodiment, the therapy delay gate, apneathreshold gate, and stimulus delay gate each have an associated timerand register, where the associated registers are in communication withan internal control bus. In still another embodiment, a stimulus counteris also included.

A method may be performed involving receiving an activity signal from anactivity detector, intercepting the activity signal with a therapy delaygate until the therapy delay has lapsed after which the signal passes toa apnea threshold gate. The apnea threshold gate intercepts the activitysignal until an apnea threshold has been exceeded after which the signalpasses to the stimulus delay gate. The stimulus delay gate interceptsthe signal until a stimulus delay has lapsed after which the signal isissued from the stimulus timer as a stimulus start signal. A stimulusrate generator may issue a stimulus rate signal and a stimulus durationtimer may issue a stimulus duration signal.

Stimulus Sequencer

A stimulus sequencer may receive a stimulus start signal, a stimulusrate signal, and a stimulus duration signal from a stimulus timer asshown in FIGS. 2A and 2B. The stimulus sequencer may then determinewhich stimulus wave shapes to be applied and in what order. For example,the stimulus sequencer may select a combination of stimuli including atone, a click, and a pop may then provide the order in which thesestimuli are used to stimulate a patient. The stimulus sequencer may thentransmit a generator select signal to a stimulus generator or othercomponents of a stimulation controller.

Referring to FIG. 6A, there is indicated more specifically by numeral 40a stimulus sequencer. The stimulus sequencer 40 receives its inputs viathe stimuli start signal 32, stimuli rate signal 34 and stimuli durationsignal 36 from the stimulus timer 30. The stimulus sequencer 40 connectsvia the generator select signal 42 to the stimulus generator. For thepurpose of inter-device communication command and control, the StimulusSequencer 40 connects to the common Device Controller Bus 92. A detaileddescription of the stimulus sequencer 40 is provided below and in aseparately filed U.S. Provisional Patent Application titled StimulusSequencer for a closed loop neuromodulator, filed on Aug. 22, 2008, thecontents of which are hereby incorporated by reference herein.

A function of the stimulus sequencer is to provide anti-habituationtherapy to avoid habituation to stimuli types in patients. In order toavoid habituation to certain stimuli types a multitude of differentstimuli types have to be generated and activated as needed in veryspecific and deliberate sequences. The sequencer activates a veryspecific stimulus generator as needed and as prescribed. The sleeppractitioner can input the stimulation sequence into the device fordiagnosis and therapy.

There is a need for fixed operation/manual mode so that the sleep labpractitioner can operate the unit in manual mode for the purpose ofexperimenting, diagnosing and prescribing the optimum range for specificsleep patient's stimuli type regimen.

Referring to FIG. 6B, the stimulus sequencer may include a sequenceaddress generator 406, a sequence memory array 418, and a stimulusgenerator selector 430. The stimulus address generator 406 may be incommunication with an internal control bus 92, through a stimulusaddress generator register 402. The stimulus memory array 418, may be incommunication with an internal control bus 92 through a sequence loadcontrol register 408, a sequence load address register 414, and asequence load data register 420. The stimulus generator selector 430 maybe in communication with an internal control bus 92 through a stimulusgenerator selector register 426.

The stimulus sequencer decides on which stimulus wave shape is to beapplied and in what order. The orders can be but are not limited to:

1. Fixed

2. Sequential

3. Circular

4. Random

5. Periodic

6. Custom

7. Patterned

8. Continuous

Fixed means that the same stimulus types are repeatedly applied everytime a stimulus is being issued

Sequential means that the stimulus types may be changed from stimulus tostimulus during the same apnea, but that the same stimulus sequencestarts over the next time an Apnea is detected.

Circular means that the stimulus types may change from stimulus tostimulus during the same apnea, but when a new apnea occurs and the nextstimulus is being issued, it will be the next stimulus in the circularsequence. The stimulus types are lined up in a circle. The circle has nospecific start or end points.

Random means that the stimulus types are issued in an arbitrarysequence. The stimulus sequence can be generated by a quasi randomsignal source (QRSS) and subsequently recorded and loaded into thesequence memory array.

Periodic means that the stimulus types are issued in a sequence that islike going up a ladder and then coming down, then going back up and soforth.

Custom means that the stimulus types are issued in a long pre-definedsequence as prescribed by the sleep practitioner.

Patterned means that the stimulus types are issued in short definedsequences as prescribed by the sleep practitioner.

Continuous means that the stimulus type is continuously issued to thetransducer/patient with the defined stimulus rate and stimulus durationwhether an apnea is present or not. This test mode allows the sleeppractitioner to listen, experience and measure the selected stimulus atwill.

An element of the stimulus sequencer is its sequence memory array whichis loaded with the sequence as selected and described above either onstart-up or during operation by the device controller who manages andkeeps track of the stimulus sequencing.

The sequence memory array is of a 256×8-bit <00Hex to <FFHex> readwritable random access memory (RAM) type. The sequence memory array canbe any size memory and is not limited to 256×8-bit.

The sleep practitioner may load the stimuli sequences as needed viaremote terminal instructions into the sequence memory array.

All load, control, address and data values are being communicated fromthe device controller through the internal control bus via theindividual registers.

The device controller communicates the sequence information of which isthe current generator being selected, which is the next generator asequence and which was the last generator selected in a sequence.

Sequence address generator range: 0 to 255 addresses

Sequence load control range: 8-bit (clear, set, reset, clock)

Sequence load address range: 8-bit (A0 . . . A7)

Sequence date load range: 8-bit (DB0 . . . DB7)

Device controller keeps track of the following: sequence start pointsand sequence end points.

Upon receipt of the stimulus start signal, the 8-bit or N-bitprogrammable sequence generator/counter selects the next stimulussequence upon receipt of the stimulus rate signal for generating thesequence of the appropriate stimulus generator. With each new stimulusduration signal clocked into the sequence address generator, a newaddress is being generated and input into the sequence memory array forselection of the particular stimulus type for that specific stimulus.

Referring to FIG. 6B, there is indicated more specifically by numeral 40a detailed block diagram of the stimulus sequencer. The input of thestimulus sequencers 40 are the stimulus start signal 32, stimulus ratesignal 34 and the stimulus duration signal 36. The stimulus start signal32 connects to sequence address generator 406 internally gated enableport. The stimulus rate signal 34 connects to the sequence addressgenerator 406 clock input port. The stimulus duration signal 36 connectsto the stimulus generator selector gated enable port. The sequenceaddress generator 406 connects to the sequence memory array 418 via theaddress selection bus 412. The sequence address generator 406 receivesits programmable count parameters through the 8-bit parallel connection404 from the sequence address generator 402. The sequence addressgenerator register 402 can be written and read-back through the 8-bitinternal control bus 92. The sequence memory array 418 connects to thestimulus generator selector 430 via the stimulus sequence data bus 424.The sequence memory array 418 receives its sequence load controlcommands through the 8-bit parallel connection 410 from the sequenceload control register 408. The sequence load control register 408 can bewritten and read-back through the 8-bit internal control bus 92. Thesequence memory array 418 receives its sequence address load commandsthrough the 8-bit parallel connection 416 from the sequence load addressregister 414. The sequence load address register 414 can be written andread-back through the 8-bit internal control bus 92. The sequence memoryarray 418 receives its sequence data load commands through the 8-bitparallel connection 422 from the sequence load data register 420. Thesequence load data register 420 can be written and read-back through the8-bit internal control bus 92. The stimulus generator selector 430receives its stimulus generator commands through the 8-bit parallelconnection 428 from the stimulus generator selector register 426. Thestimulus generator selector register 426 can be written and read-backthrough the 8-bit internal control bus 92. The stimulus generatorselector 430 connects to the stimulus generator via the 8-bit stimulusgenerator data bus 42.

Referring to FIG. 6C, there is indicated more specifically by numeral4002 a detailed stimulus sequence timing diagram for the various typesof aforementioned stimulus.

The stimulus sequencer disclosed herein may help to avoid habituation tostimuli types in patients. In order to avoid habituation to certainstimuli types a multitude of different stimuli types may be generatedand activated as needed in very specific and deliberate sequences. Thesequencer activates a very specific stimulus generator as needed and asprescribed. The sleep practitioner can input the stimulation sequenceinto the device for diagnosis and therapy.

The sequencer may be capable of a fixed operation/manual mode so thatthe sleep lab practitioner can operate the unit in manual mode for thepurpose of experimenting, diagnosing and prescribing the optimum rangefor specific sleep patient's stimuli type regimen.

Stimulus Generator

A stimulus generator may receive a generator select signal from astimulus sequencer as shown in FIGS. 2A and 2B. The generator selectsignal may contain a sequence of stimulus types in a specific order andmay also define the duration of each stimulus. The stimulus generatormay include individual generators for each stimulus type available suchas one generator for generating a hiss signal, another generator forgenerating a click signal, and additional types as discussed below. Thestimulus generator processes the generator select signal by signalingthe individual generators defined by the generator select signal togenerate a stimulus signal for the duration also defined by thegenerator select signal. The stimulus generator may then emit a stimulussignal to a stimulus escalator or other portions of a stimulationcontroller.

Referring to FIG. 7A, there is indicated more specifically by numeral 50a stimulus generator. The stimulus generator 50 receives its inputs viathe stimuli select signal 42, from the stimulus sequencer 40. Thestimulus generator 50 connects via the stimuli signal 52 to the stimulusescalator 60. For the purpose of inter-device communication command andcontrol, the Stimulus Generator 50 connects to the common DeviceController Bus 92. A detailed description of the stimulus generator 50is provided below and in a separately filed U.S. Provisional PatentApplication titled Stimulus Generator for a closed loop neuromodulator,filed on Aug. 22, 2008, the contents of which are hereby incorporated byreference herein.

A function of the stimulus generator is to provide different types ofstimuli in order to avoid habituation to stimuli signal in patients. Inorder to avoid habituation to certain stimuli types a multitude ofdifferent stimuli types have to be generated and activated as needed.The sleep practitioner can input the stimulation sequence into thedevice for diagnosis and therapy.

There is a need for fixed operation/manual mode so that the sleep labpractitioner can operate the unit in manual mode for the purpose ofexperimenting, diagnosing and prescribing the optimum range for specificsleep patient's stimuli regimen.

The stimulus generator delivers the stimulus type according either whatthe sleep practitioner has prescribed or what the auto-adjusting routinehas determined to be the optimal stimulus type for the particularpatient. The stimulus types can be but either single or a combinationthereof, but is not limited to:

1. Tone

2. Click

3. Pop

4. Noise

5. Hiss

6. Modulated

7. Siren

8. Warble

9. Custom

Tone means that the stimulus type is harmonic in nature such assinusoidal, square, trapezoidal, triangular, saw tooth, etc type signalwaveforms. A tone may sound similar to a tone played on an instrument.

Click means that the stimulus type is a single, abrupt and sharpwaveform transition generating a wide frequency spectrum. A click maysound similar to a single sharp hand clap or door slamming shut.

Pop means that the stimulus type is a single but less sharp waveformtransition generating a narrow frequency spectrum. A pop may soundsimilar to a bottle of Champaign being opened or a thunderclap from asingle but distant lightning strike.

Noise means that the stimulus type is constant and consists of allfrequency components in the relevant frequency band of interest. Whitenoise for example has a very evenly distributed frequency spectrum andits power distribution is constant over a wide frequency range. Pinknoise for example has a constant power density in a given octavefrequency ratio of F2/F1=2, were F2 is the higher frequency and F1 isthe lower frequency. White noise sounds rather sharp whereas pink noisesounds rather mellow. A noise signal may sound similar to a TV or Radiowith the transmitter turned off or similar to the sound of a high speedtrain passing by.

Hiss means that the stimulus type is constant and consists of allfrequency components however experiencing natural signal growth andsignal decay. A hiss may sound like steam escaping from a vent or anangry cat or an agitated snake.

Modulated means that the stimulus type is being modulated by anothersignal similar to an amplitude modulation (AM) or frequency modulation(FM). A modulated sound does not sound remind of anything from thisworld. Most modulated sounds find applications in science fictionmovies.

Siren means that the stimulus type is being modulated by high frequencyascending and descending waveform. A siren will sound like a police caretrying to get the drivers attention.

Warble means that the stimulus type is being modulated by low frequencyascending and descending waveform. A warble may sound like a piece ofmachinery working normally or working under stress.

A custom stimulus generator provides a custom stimulus signal type, forexample, but not limited to, a recording of a person's voice, such asthat of crying baby to subliminally stimulate a mother's central nervoussystem.

The sleep practitioner may load the stimulus generator combinations asneeded via remote terminal instructions into the sequence memory array.

The sleep practitioner may also load the stimulus generator frequencies,intensities and combinations as needed via remote terminal instructionsinto the appropriate stimulus generator registers.

All load, control, address and data values are being communicated fromthe device controller through the internal control bus via theindividual registers.

The device controller communicates the information of which is thecurrent generator or combination is being selected.

Tone stimulus generator range: 0 to 255 variations

Click stimulus generator range: 0 to 255 variations

Pop stimulus generator range: 0 to 255 variations

Noise stimulus generator range: 0 to 255 variations

Hiss stimulus generator range: 0 to 255 variations

Modulated stimulus generator range: 0 to 255 variations

Siren stimulus generator range: 0 to 255 variations

Warble stimulus generator range: 0 to 255 variations

Referring to FIG. 7B, there is indicated more specifically by numeral 50a detailed block diagram of the stimulus generator. The input of thestimulus generator 50 is the stimulus generator select signal 42. Thegenerator select signal 42 connects to the bank of stimulus tonegenerators 506, 516, 526, 536, 546, 556, 566, and 576. The stimulusgenerator select signal 42 connects to the sequence address generator406 input select port. The generator signal 42 connects to the tonestimulus generator 506 Gen A enable port. The tone stimulus generator506 connects to the stimulus generator-summing amplifier 580 viaconnection 508. The tone stimulus generator 506 receives itsprogrammable parameters through the 8-bit parallel connection 504 fromthe tone stimulus generator register 502. The tone stimulus generatorregister 502 can be written and read-back through the 8-bit internalcontrol bus 92. The generator signal 42 connects to the click stimulusgenerator 516 Gen B enable port. The click stimulus generator 516connects to the stimulus generator-summing amplifier 580 via connection518. The click stimulus generator 516 receives its programmableparameters through the 8-bit parallel connection 514 from the clickstimulus generator register 512. The click stimulus generator register512 can be written and read-back through the 8-bit internal control bus92. The generator signal 42 connects to the pop stimulus generator 526Gen C enable port. The pop stimulus generator 526 connects to thestimulus generator-summing amplifier 580 via connection 528. The popstimulus generator 526 receives its programmable parameters through the8-bit parallel connection 524 from the pop stimulus generator register522. The pop stimulus generator register 522 can be written andread-back through the 8-bit internal control bus 92. The generatorsignal 42 connects to the noise stimulus generator 536 Gen D enableport. The noise stimulus generator 536 connects to the stimulusgenerator-summing amplifier 580 via connection 538. The noise stimulusgenerator 536 receives its programmable parameters through the 8-bitparallel connection 534 from the noise stimulus generator register 532.The noise stimulus generator register 532 can be written and read-backthrough the 8-bit internal control bus 92. The generator signal 42connects to the hiss stimulus generator 546 Gen E enable port. The hissstimulus generator 546 connects to the stimulus generator-summingamplifier 580 via connection 548. The hiss stimulus generator 546receives its programmable parameters through the 8-bit parallelconnection 544 from the hiss stimulus generator register 542. The hissstimulus generator register 542 can be written and read-back through the8-bit internal control bus 92. The generator signal 42 connects to themodulated stimulus generator 556 Gen F enable port. The modulatedstimulus generator 556 connects to the stimulus generator-summingamplifier 580 via connection 558. The modulated stimulus generator 556receives its programmable parameters through the 8-bit parallelconnection 554 from the modulated stimulus generator register 552. Themodulated stimulus generator register 552 can be written and read-backthrough the 8-bit internal control bus 92. The generator signal 42connects to the siren stimulus generator 566 Gen G enable port. Thesiren stimulus generator 566 connects to the stimulus generator-summingamplifier 580 via connection 568. The siren stimulus generator 566receives its programmable parameters through the 8-bit parallelconnection 564 from the siren stimulus generator register 562. The sirenstimulus generator register 562 can be written and read-back through the8-bit internal control bus 92. The generator signal 42 connects to thewarble stimulus generator 576 Gen H enable port. The warble stimulusgenerator 576 connects to the stimulus generator-summing amplifier 580via connection 578. The warble stimulus generator 576 receives itsprogrammable parameters through the 8-bit parallel connection 574 fromthe warble stimulus generator register 572. The warble stimulusgenerator register 572 can be written and read-back through the 8-bitinternal control bus 92. The stimulus generator-summing amplifier 580connects to the stimulus escalator via the stimulus signal 52.

A single selected stimulus generator issues one pulse of its specificsignal type for the length of the incoming stimulus duration.

The stimulus generator described herein may provide anti-habituatingsleep therapy using different types of stimuli in order to avoid patienthabituation to the stimuli signal. In order to avoid habituation tocertain stimuli types, a multitude of different stimuli types may begenerated and activated as needed. The sleep practitioner can input thestimulation sequence into the device for diagnosis and therapy.

The device may also provide for a fixed operation/manual mode so thatthe sleep lab practitioner can operate the unit in manual mode for thepurpose of experimenting, diagnosing and prescribing the optimum rangefor specific sleep patient's stimuli regimen.

In one embodiment, a stimulus generator for a closed loop neuromodulatorincludes a plurality of stimulus generators, corresponding plurality ofstimulus generator registers, and a stimulus generator summingamplifier. The plurality of stimulus generators may include eightstimulus generators each directed at different generating differentstimuli. The eight stimulus generators may include a tone generator, aclick generator, a pop generator, a noise generator, a hiss generator, amodulated generator, a siren generator, and a warble generator.

Stimulus Escalator

A stimulus escalator may receive a stimulus signal 52, a stimulus startsignal 32, and a stimulus rate signal 34 from a stimulus generator asshown in FIGS. 2A and 2B. In an effort to avoid overly stimulating asleep patient it is often effective to start with a relatively low levelstimulus and increase the stimulus level until the appropriate level isreached. The stimulus escalator implements this rationale, by receivingthe input signals listed above and emitting a corresponding driversignal with a given level signal. The stimulus escalator may determinehow to increase each signal (e.g. linearly, exponentially, etc.)

Referring to FIG. 8A, there is indicated more specifically by numeral 60a stimulus escalator. The stimulus escalator 60 receives its inputs viathe stimulus signal 52 from the stimulus generator 50 and stimulus startsignal 32 and stimuli rate signal 34 from the stimulus timer 30. Thestimulus escalator 60 connects via the driver signal 62 to the EMI/ESDhardened transducer driver 70. For the purpose of inter-devicecommunication command and control, the Stimulus Escalator 60 connects tothe common Device Controller Bus 92. A detailed description of thestimulus escalator 60 is provided below and in a separately filed U.S.Provisional Patent Application titled Stimulus Escalator for a closedloop neuromodulator, filed on Aug. 22, 2008, the contents of which arehereby incorporated by reference herein.

A function of the stimulus escalator is to provide anti-habituatingsleep therapy to avoid habituation to stimuli levels in patients. Inorder to avoid habituation to certain stimuli levels a multitude ofdifferent stimuli levels have to be generated and activated as needed invery specific and deliberate level escalation. The escalator activates avery specific stimulus level as needed and as prescribed. The sleeppractitioner can input the stimulation escalation gain and escalationenvelope function via an escalation table into the device for diagnosisand therapy.

There is a need for fixed operation/manual mode so that the sleep labpractitioner can operate the unit in manual mode for the purpose ofexperimenting, diagnosing and prescribing the optimum range for specificsleep patient's stimuli level regimen.

The stimulus escalator decides on which stimulus level is to be appliedand with what escalation envelope function. The envelope functions canbe but are not limited to:

1. Constant

2. Linear

3. Polynomial

4. Exponential

5. Logarithmic

Constant means that the same stimulus level escalation envelope functionis constant that the same stimulus level is repeatedly applied everytime a stimulus is being issued.

Linear means that the same stimulus level escalation envelope functionis linear and in the form Y=Ax+B so that the next applied stimulus obeysthe aforementioned mathematical relationship with the previously issuedstimulus.

Polynomial means that the same stimulus level escalation envelopefunction is polynomial and in the form Y=A*x²+B*x+C so that the nextapplied stimulus obeys the aforementioned mathematical relationship withthe previously issued stimulus.

Exponential means that the same stimulus level escalation envelopefunction is polynomial and in the general form Y=A*e^(−(x/B)), so thatthe next applied stimulus obeys the aforementioned mathematicalrelationship with the previously issued stimulus.

Logarithmic means that the same stimulus level escalation envelopefunction is polynomial and in the general form Y=A*Log_(n) (B*x), sothat the next applied stimulus obeys the aforementioned mathematicalrelationship with the previously issued stimulus.

An element of the stimulus escalator is its escalation memory arraywhich is loaded with the escalation level envelope values as selectedand described above either on start-up or during operation by the devicecontroller who manages and keeps track of the stimulus sequencing.

The escalation memory array is of a 256×8-bit <00Hex to <FFHex> readwritable random access memory (RAM) type. The escalation memory arraycan be any size memory and is not limited to 256×8-bit.

The sleep practitioner may load the escalation values as needed viaremote terminal instructions into the escalation memory array.

All load, control, address and data values are being communicated fromthe device controller through the internal control bus via theindividual registers.

The device controller communicates the escalation information of whichis the current stimulus level, which is the next stimulus level andwhich was the last stimulus level issued.

Escalation address generator range: 0 to 255 addresses

Escalation load control range: 8-bit (clear, set, reset, clock)

Escalation load address range: 8-bit (A0 . . . A7)

Escalation date load range: 8-bit (DB0 . . . DB7)

The device controller keeps track of the following: escalation startlevels and escalation end levels.

Upon receipt of the stimulus start signal, the 8-bit or N-bitprogrammable escalation generator/counter selects the next escalationlevel upon receipt of the stimulus rate signal for generating theescalation level of the appropriate stimulus generator. With each newstimulus duration signal clocked into the escalation address generator,a new address is being generated and input into the escalation memoryarray for selection of the particular stimulus level for that specificstimulus.

Referring to FIG. 8B, there is indicated more specifically by numeral 60a detailed block diagram of the stimulus escalator. The inputs of thestimulus escalator 60 are the stimulus start signal 32, the stimulusrate signal 34 and the stimulus signal 52. The stimulus start signal 32connects to the escalation address generator 606 internally gated enableport. The stimulus rate signal 34 connects to the escalation addressgenerator 606 clock input port. The escalation address generator 606connects to the escalation memory array 618 via the address selectionbus 612. The escalation address generator 606 receives its programmablecount parameters through the 8-bit parallel connection 604 from theescalation address generator 602. The escalation address generatorregister 602 can be written to and read-back from the 8-bit internalcontrol bus 92. The escalation memory array 618 connects to theprogrammable gain amplifier 630 via the escalation data bus 624. Theescalation memory array 618 receives its escalation load controlcommands through the 8-bit parallel connection 610 from the escalationload control register 608. The escalation load control register 608 canbe written to and read-back from the 8-bit internal control bus 92. Theescalation memory array 618 receives its escalation address loadcommands through the 8-bit parallel connection 616 from the escalationload address register 614. The escalation load address register 614 canbe written and read-back through the 8-bit internal control bus 92. Theescalation memory array 618 receives its escalation data load commandsthrough the 8-bit parallel connection 622 from the escalation load dataregister 620. The escalation load data register 620 can be written toand read-back from the 8-bit internal control bus 92. The programmablegain amplifier 630 receives its gain setting data through the 8-bitparallel connection 628 from the programmable gain amplifier register626. The programmable gain amplifier register 626 can be written to andread-back from the 8-bit internal control bus 92. The programmable gainamplifier 430 connects to the EMI/ESD hardened transducer driver via thedriver signal 62.

The programmable gain amplifier 430 can be programmed in 0.3 dB gainsteps per bit. In a gain block the gain is expressed in decibel (dB).Loss or gain is expressed in dB. The loss/gain range of the programmablegain amplifier is about 76.5 dB but more or less possible.

In one embodiment, a stimulus escalator for a closed loop neuromodulatorincludes an escalation address generator, an escalation register array,and a programmable gain amplifier. In another embodiment, the stimulusescalator further includes an escalation address generator register,where the escalation address generator is configured to receiveescalation addresses from the escalation address generator register. Inanother embodiment, the stimulus escalator further includes anescalation load control register, an escalation load address register,and an escalation load data register. In yet another embodiment, thestimulus escalator further includes a programmable gain amplifierregister.

EMI/ESD Hardened Transducer Driver

A transducer driver may receive input from a stimulus escalator and maythen transmit this signal to a transducer, as shown in FIGS. 2A and 2B.Moreover, as also depicted in FIGS. 2A and 2B, this sensor interface maybe the final output or exit location for a stimulation controller andmay therefore be a potential inlet for EMI and ESD. Thus, the transducerdriver may be equipped with EMI and ESD protection to preventinterference with and/or damage to the transducer driver or the overallcontroller.

Referring to FIG. 9A, there is indicated more specifically by numeral 70an EMI/ESD hardened transducer driver. The EMI/ESD hardened transducerdriver 70 receives its input via the driver signal 62 from the output ofthe stimulus escalator 60. The EMI/ESD hardened transducer driver 70connects via the pair of wire terminals 5 to the transducer 6. Adetailed description of the EMI/ESD hardened transducer driver 70 isprovided below and in a separately filed U.S. Provisional PatentApplication titled EMI/ESD Hardened Transducer Driver for a closed loopneuromodulator, filed on Aug. 22, 2008, the contents of which are herebyincorporated by reference herein.

Even though most countries have legal requirements that mandate EMCcompliance, electronic devices must still work correctly when subjectedto certain amounts of electromagnetic interference (EMI), and should notemit EMI, which could interfere with other equipment. This issue isknown in the industry as self-compatibility and this fact is crucial tothe operation of the invention because of the very low analog biomedicalsignals involved.

A robust sleep therapy system works reliably in a modern harsh andhostile environment in close proximity to cell phone transmissions,wireless internet transmitters, wireless phone system transmitters, etc.Modern environments, even home environments have high concentration ofEMI and RFI especially in the 60 Hz/120 Hz due to home power wiring andfluorescent, compact fluorescent lighting and switch mode power suppliesoperating in home appliances. Additionally, wireless technology such aswireless telephone transmissions, wireless routers, cordless phonesystems, remote control burglar alarm devices, remote control toys, andthe like may emit EMI. Issues of self-compatibility are also a concernand involve minimizing the emission of EMI that could interfere withother portions of the device or other equipment. Thus, EMI that couldinterfere with a sleep device is a concern, but the EMI emitted by thedevice is also a concern.

ESD hardening protects sensitive electronic due to common and regularhandling of the product containing the sensitive electronics in astandard home environment were static discharges are common especiallyduring the winter seasons in colder climate zones and during the dryseasons in warmer climate zones.

EMI/ESD hardening against the aforementioned offenders not onlysatisfies domestic and international requirements on emissions andsusceptibility but also results in robust operation, cleaner internalsignals, improved signal-to-noise-ratio (SNR) and greater dynamic range.

Due to the nature of the device application, through its typical longsensor and transducer wires, exposure of the output to ESD maypotentially destroy the transducer driver circuitry. Thus, special ESDcountermeasures have to be put in place in order to prevent damage ortotal destruction of the sensitive, low power circuitry.

The following is a list of EMC component level countermeasures for theEMI/ESD hardened transducer driver:

1. Feed-through capacitors

2. Balanced drive amplifier

3. Matched gain setting resistor network to maintaining high CMRR

4. Ferrite beads, series EMI suppression element

5. Filter capacitors, parallel EMI suppression element

6. Common mode RF filter, parallel EMI suppression element

7. Common mode RF choke, series EMI suppression element

8. Capacitor as signal decoupling, parallel EMI suppression element

9. Inductor as signal lead filtering, series EMI suppression element

10. Capacitor as power feed filtering, parallel EMI suppression element

11. Inductor as power feed filtering, series EMI suppression element

12. Schottky diodes, EMI suppression parallel element

13. Resistors, series EMI suppression element

14. Inductors, series EMI suppression element

15. Cascaded capacitor banks, 0.01 uf and 10 uF

16. Inductors in V+ and V− feeds before capacitor cascade, power feedoutput

For the purpose of EMI/RFI shielding of the EMI/ESD hardened transducerdriver 70, a metal case is mounted on to of the PCB picket fencedcircuit boundary. The picket fence is connected to the ground pane andground flooded signal layer.

The following is a list of PCB based EMC countermeasures for the EMI/ESDhardened transducer driver:

1. Power and ground planes

2. Layer flooding

3. Picket fencing

4. Short and narrow signal traces

5. Short and wide power traces

6. Components must be placed in close proximity to each other

7. PCB routing must be as short as possible

8. Short and wide traces are better than long and skinny ones

The following operational parameters that are adjustable within theEMI/ESD hardened sensor Interface:

1. Amplifier Gain (−20 dB to +20 dB)

Referring to FIG. 9B there is indicated more specifically by numeral 70a detailed block diagram of the EMI/ESD hardened transducer driver. Theinput signal 42 for the EMI/ESD hardened transducer driver 70 is beinggenerated by the output of the stimulus escalator. The supply filteredbalanced drive amplifier 704 amplifies the input signal 42 to match theappropriate drive level of the externally connected transducer 6. Thebalanced output wire pair 720 of the supply filtered balanced driveamplifier connects to the ESD protection circuit 706. The balancedoutput wire pair 722 of the ESD protection circuit 706 connects to theinternal EMI/RFI filter 708. The balanced output wire pair 724 of theinternal EMI/RFI filter 708 penetrates the metal casing 701 and connectsto the external EMI/RFI filter. The balanced output wire pair 726 of theexternal EMI/RFI filter connects to the transducer output connector 712.The metal shield 701 covers as the sensitive signal carrying analogsignal circuit as indicated and is connected to a multitude of ¼″ spacedground connections 701 for providing a very low impedance connection tocircuit ground even at extremely high frequencies. The metal shield 701in connection with the printed circuit ground plane on the opposite sideof the PCB and with an RF tight picket fence constructed of interleavedvias that connect the ground plane to the ground flooded top componentcopper layer forms a continuous electrostatic shield around the entirevolume of the EMI/ESD hardened transducer driver 70.

Referring to FIG. 9C, there is indicated a schematic diagramspecifically by numeral 70 an EMI/ESD hardened transducer driver.

The input signal 42 for the EMI/ESD hardened transducer driver 50 isbeing generated by the output of the stimulus escalator. The supplyfiltered balanced drive amplifiers 704 comprise of operationalamplifiers (opamps) U1 and U2. Both opamps U1 and U2 are connected in atwo-amplifier balanced drive amplifier configuration. The balancedamplifier gain is set by the ratio of the resistors R2/R1 and R4/R3.Resistor R2 by means of connection to signal ground provides driftcompensation for opamp U1. Resistor R5 by means of connection to signalground provides drift compensation for opamp U2. Negative supplyfiltering of the operational amplifier U1 comprises of a conducted RFpower absorbing inductor L1 and a conducted RF power suppressingcascaded capacitor bank consisting of C1 and C3 in parallel to ground.The conducted RF power absorbing inductor L1 is connected in series withthe negative supply power terminal V− and the negative power supplyterminal 2 of the operational amplifier U1. Positive supply filtering ofthe operational amplifier U1 comprises of a conducted RF power absorbinginductor L2 and a conducted RF power suppressing cascaded capacitor bankconsisting of C2 and C5 in parallel to ground. The conducted RF powerabsorbing inductor L2 is connected in series with the positive supplypower terminal V+ and the positive power supply terminal 5 of theoperational amplifier U1. Furthermore, conducted emissions bypassingcapacitor C4 is connected across the U1 operational amplifier power pin2 and pin 5. Negative supply filtering of the operational amplifier U2comprises of a conducted RF power absorbing inductor L3 and a conductedRF power suppressing cascaded capacitor bank consisting of C6 and C8 inparallel to ground. The conducted RF power absorbing inductor L3 isconnected in series with the negative supply power terminal V− and thenegative power supply terminal 2 of the operational amplifier U2.Positive supply filtering of the operational amplifier U2 comprises of aconducted RF power absorbing inductor L4 and a conducted RF powersuppressing cascaded capacitor bank consisting of C7 and C10 in parallelto ground. The conducted RF power absorbing inductor L4 is connected inseries with the positive supply power terminal V+ and the positive powersupply terminal 5 of the operational amplifier U2. Furthermore,conducted emissions bypassing capacitor C9 is connected across the U2operational amplifier power pin 2 and pin 5. The balanced ended outputof the supply filtered balanced drive amplifier 704 connects to theoutput ESD protection 706. The ESD protection 706 comprises primarily ofdiodes D1, D2, D3 and D4. The cathode of D1 is connected to the positivesupply terminal. The anode of D1 is connected to the output terminal 1of opamp U1. The anode of D2 is connected to the negative supplyterminal. The cathode of D2 is connected to the output terminal 1 ofopamp U1. The cathode of D4 is connected to the positive supplyterminal. The anode of D4 is connected to the non-inverting inputterminal 3 of opamp U2. The anode of D3 is connected to the negativesupply terminal. The cathode of D3 is connected to the non-invertinginput terminal 3 of opamp U2. D1 through D4 present the parallelclamping element of the ESD protected opamp input terminal. Resistors R7and R8 in connection with the Diodes D1, D2, D3 and D4 form an ESDsuppression circuit. Resistors R7 and R8 form the series ESD powerabsorbing elements. It is clearly shown that the output terminal 1 ofthe operational amplifiers U1 and U2 of the supply filtered balanceddrive amplifier 704 are EMI and ESD protected. The internal EMI/RFIfilter 708 comprises a differential mode filtering capacitor C15connected to C16 and C17. Also connected to C16 and C17 is the inputwire pair of a high frequency common mode choke L5. The output wire pairof the high frequency common mode choke L5 is connected to the input ofthe two ESD energy absorbing series resistors R7 and R8 and to a secondfilter capacitor C14. The output wire pair of the energy absorbingresistors R7 and R8 is connected to another set of EMI suppressingfilter capacitors C11 C12 and C13. The sensor output connector 712comprises of connector J2 with the two-signal wire pair leads designatedas pin 1 and pin 2 respectively. The external EMI/RFI 710 filtercomprises of a pair of ferrite beads FB1 and FB2 acting as the filterseries element, and of a pair of metal shield penetrating feed-throughcapacitors C16 and C17 as the parallel element to ground for common modefiltering. The EMI/ESD hardened transducer driver 70 is designed todrive various transducer types.

The following is a list of possible transducers that may be connected tothe EMI/ESD hardened transducer driver 70.

Acoustic transducers by which a sound is introduced into the ear canalor the room to disrupt the undesired behavior and pattern.

Ultrasonic transducers by which an audio tone is used to modulate anultrasonic beam directed at the patient. The brain demodulates thesignal and the detected audio signal is perceived as such. Theultrasonic beam is very narrow thus; only the patient is subjected toit, the rest of the space remains quiet and unaffected. Therefore, noaural ear bud phones would be needed.

Tactile transducers by which a mechanical device such as the mechanicalagitator applies a gentle touch to the patient's skin.

Visual transducers by which a flash of light is applied to the eyes. Aneye cover with red LED which would turn on for a short amount of timeduring stimulation.

Puff-of-Air transducers by which an air puff is applied to the patient'sskin.

Electrical transducers (biomedical electrodes) by which a gentleelectrical stimulation is applied to the patient's skin.

Alternatively, a signal duplexer can be used in order to utilize thesame PVDF sensor that is detecting airflow with pyroelectric andpiezoelectric properties as the stimuli delivering transducer. Thepyroelectric and piezoelectric properties of the PVDF film arereciprocal. This is because the piezoelectric capability of the filmincluded either converting mechanical vibrations to electrical signalsand/or converting electrical signals to mechanical, including audio orultrasound vibrations.

In one embodiment, an EMI/ESD hardened transducer driver for a closedloop neuromodulator includes a supply filtered balanced drive amplifier,an ESD protection device, at least one EMI/RFI filter, a grounded metalshield, and a transducer output connector. In another embodiment, bothan internal and an external EMI/RFI filter are provided. In anotherembodiment, the external EMI/RFI filter is situated along a signal pathoutside the grounded metal shield. In yet another embodiment, theinternal EMI/RFI filter is situated along a signal path inside thegrounded metal shield. In another embodiment, each of the elements arearranged in series.

Diagnostic Indicator and PSG Interface

In sleep medicine, a stimulation controller may be used to receive inputfrom a sensor on a patient, analyze the input, and further may be usedto activate a transducer to stimulate the patient. FIGS. 1A and 1B showat least two embodiments of a stimulation controller in position on apatient. The following description relates to a diagnostic indicator andPSG interface included in a stimulation controller.

As shown in FIGS. 2A and 2B, the diagnostic indicator and PSG interfacemay receive input from various devices in a stimulation controller. Thepurpose of the diagnostic indicator is to provide an indication to theuser or the sleep practitioner of what information the stimulationcontroller is receiving, what functions it is performing, and whatinformation it is transmitting. The diagnostic indicator may include aseries of LED's indicating such information. Additionally, thediagnostic indicator and PSG interface may be compatible with a PSGmachine and thereby provide a sleep practitioner with more sophisticatedoutput beyond LED output.

A detailed description of the Diagnostic Indicator and PSG Interface 80is provided below and in a separately filed U.S. Provisional PatentApplication titled Diagnostic Indicator and PSG Interface for a closedloop neuromodulator, filed on Aug. 22, 2008, the contents of which arehereby incorporated by reference herein.

Referring to FIG. 10A, there is indicated more specifically by numeral80 a Diagnostic Indicator and PSG Interface. The Diagnostic Indicatorand PSG Interface 80 receives multiple inputs from the other elements ofthe closed loop neuromodulator. The following signals are inputs to theDiagnostic Indicator and PSG Interface 80: The Analog airflow signal 130and the digital airflow signal 12 from the EMI/ESD Hardened SensorInterface, the activity signal 22, from the Activity detector, thestimuli signal 52 from the Stimulus Generator and the driver signal 62from the Stimulus Escalator. A push button switch 38 also connects tothe Diagnostic Indicator and PSG Interface 80 via the push button inputconnection 39 for the purpose of activating the sleep therapy delaytimer. The following signals are outputs from the Diagnostic Indicatorand PSG Interface 80: The therapy delay indicator 81, the inhalationindicator 82, the power indicator 83, the therapy mode indicator 84, theapnea indicator 85, the apneas detected indicator 86, the diagnosticmode indicator 87, the exhalation indicator 88, and the stimulusindicator 89. The Diagnostic Indicator and PSG interface 80 connects viathe PSG connection 7 to the PSG machine 8. A detailed description of thestimulus escalator 40 is provided below.

The diagnostic indicator and PSG interface provide a simplehuman-machine interface for indicating internal device operation andconnection to external diagnostic instrumentation such as a PSG forfurther analysis of patient data gathered by the closed loopneuromodulator.

Pushing the therapy delay button when the unit is in therapy delay mode,de-activates the therapy delay mode, turns the therapy delay indicatoroff and resets the count down timer.

The therapy delay indicator 81 notifies the sleep practitioner orpatient that the therapy delay timer is active and that the device willnot provide any therapy until that indicator turns off

The inhalation indicator 82 notifies the sleep practitioner or thepatient that the patient respiration cycle is currently in theinhalation phase.

The power indicator 83 notifies the sleep practitioner or the patientthat the power to the closed loop neuromodulator is turned on and thatthe device has passed its self-test routing.

The therapy mode indicator 84 notifies the sleep practitioner or thepatient that the closed loop neuromodulator is currently in therapymode.

The apnea indicator 85 notifies the sleep practitioner that the patientis currently experiencing a sleep apnea episode or any other CNSdisorder that the modulator is configured for.

The apneas detected indicator 86 notifies the sleep practitioner or thepatient that the patient has experienced sleep apneas during the currenttherapy or diagnostic cycle.

The diagnostic mode indicator 87 notifies the sleep practitioner or thepatient that the closed loop neuromodulator is currently in therapymode.

The exhalation indicator 88 notifies the sleep practitioner or thepatient that the patient respiration cycle is currently in theexhalation phase.

The stimulus indicator 89 notifies the sleep practitioner that thepatient is currently experiencing a sleep apnea episode and that astimulus is currently being applied.

Referring to FIG. 10B, there is indicated more specifically by numeral80 a detailed block diagram of the diagnostic indicator and PSGinterface. The Diagnostic Indicator and PSG Interface 80 receivesmultiple inputs from the other elements of the closed loopneuromodulator. The Analog airflow signal 130 connects to the airflowsignal buffer 828. The Airflow signal buffer output 830 connects to theinput of the Analog airflow output 832. The analog airflow output port834 is bundled together with the PSG connection port 7. The stimulisignal 52 connects to the stimulus signal buffer 812. The stimuli signalbuffer output 814 connects to the input of the stimulus marker output816. The stimulus marker output port 818 is bundled together with thePSG connection port 7. The driver signal 62 connects to the driversignal buffer 820. The driver signal buffer output 820 connects to theinput of the stimulus sound monitor output 824. The stimulus soundmonitor output 826 is bundled together with the PSG connection port 7.The digital airflow signal 12 connects to the digital airflow signalbuffer 802. The Digital airflow signal buffer 802 separates theinhalation phase of the digital airflow signal 12 from the exhalationphase of the digital airflow signal 12. The exhalation output port 804of the digital airflow signal buffer 802 drives the Exhalation LEDdriver 854. The output of the exhalation LED driver 854 drives theexhalation indicator 88. The inhalation output port 806 of the digitalairflow signal buffer 802 drives the inhalation LED driver 852. Theoutput of the inhalation LED driver 852 drives the inhalation indicator82. The activity signal 22 connects to the activity signal buffer 810.The activity signal buffer output port 808 of the activity signal buffer810 drives the input of the apnea LED driver 850. The output of theapnea LED driver 850 drives the apnea indicator 85. The push buttonswitch connection 39 connects to the push button latch 868. The pushbutton latch output 870 connects to a single bit read port of thediagnostic indicator register 836. After the diagnostic indicator,register 836 has accessed and read the status of the push button latch868, the push button latch 868 clears and is ready to accept anotherpush button activation. The diagnostic indicator register 836 can bewritten to and read-back from the 8-bit internal control bus 92. Writingto the diagnostic indicator register 836 sets or resets the LED driverdriving output bits. The output port 838 of the diagnostic indicatorregister 836 drives the Apneas detected LED driver 856. The output ofthe Apneas detected LED driver 856 drives the apneas detected indicator86. The output port 840 of the diagnostic indicator register 836 drivesthe power-on LED driver 858. The output of the power-on LED driver 858drives the power-on indicator 83. The output port 842 of the diagnosticindicator register 836 drives the therapy delay LED driver 860. Theoutput of the therapy delay LED driver 860 drives the therapy delayindicator 81. The output port 844 of the diagnostic indicator register836 drives the diagnostic mode LED driver 862. The output of thediagnostic mode LED driver 862 drives the diagnostic mode indicator 87.The output port 846 of the diagnostic indicator register 836 drives thetherapy mode LED driver 864. The output of the therapy mode LED driver864 drives the therapy mode indicator 84. The output port 848 of thediagnostic indicator register 836 drives the stimulus LED driver 866.The output of the stimulus LED driver 866 drives the stimulus indicator89.

In one embodiment, a diagnostic indicator for a closed loopneuromodulator includes a plurality of incoming signal buffers, adiagnostic indicator register, and a plurality of LED drivers. Inanother embodiment, a stimulus marker output is also included. Inanother embodiment, the diagnostic indicator includes a stimulus soundmonitor output. In yet another embodiment, an analog airflow output isincluded. In still another embodiment, a push button latch is included.

In another embodiment, a method of using a PSG machine in conjunctionwith a stimulation controller is provided.

Device Controller and Data Logger

In sleep medicine, a stimulation controller may be used to receive inputfrom a sensor on a patient, analyze the input, and further may be usedto activate a transducer to stimulate the patient. FIGS. 1A and 1B showat least two embodiments of a stimulation controller in position on apatient. The following description relates to a device controller anddata logger included in a stimulation controller for interfacing with awide range of sensors.

The device controller and data logger, as shown in FIGS. 2A and 2B, maybe placed in communication with various elements of a closed loopneuromodulator via an internal control bus. Each element of the closedloop neuromodulator may contain a register or series of registers thatthe device controller and data logger is in communication with. Thedevice controller and data logger can write to and read from the severalregisters throughout the closed loop neuromodulator and log informationas well as interpret and react to the information. The device controllerand data logger can then write new information to the several registersthroughout the closed loop neuromodulator. Parameters relating tostimulus type, stimulus rate, stimulus duration, stimulus level,stimulus escalation, and stimulus sequence are all adjustable forpurposes of precisely dosing sleep patients.

The above functions can be completed without the support of sleeppractitioner supervision. However, the device controller and data loggermay be placed in communication with a remote diagnostic terminal whichallows a sleep practitioner to modify various settings within the closedloop neuromodulator to allow for more precise dosing of patients.

A detailed description of the Device Controller and Data Logger 90 isprovided below and in a separately filed U.S. Provisional PatentApplication titled Device Controller and Data Logger for a closed loopneuromodulator, filed on Aug. 22, 2008, the contents of which are herebyincorporated by reference herein.

Referring to FIG. 11A, there is indicated more specifically by numeral90 a device controller and data logger. The common device controller anddata logger 90 is connected on the external side to the remotediagnostic terminal 14 and on the internal side to the device controllerbus 92. A detailed description of the device controller and data logger90 is provided below.

A purpose of the device controller and data logger provides aninter-device communication command and control for the closed loopneuromodulator. Furthermore, the device controller and data loggerprovides an external communication interfaced to the remote terminal forthe closed loop neuromodulator. In addition, the state controller withinthe device controller executes the state-by-state instructions of theauto-adjusting routing, the auto-optimizing routine and the auto-dosingroutine. Those routines are described in detail below.

Referring to FIG. 11B, there is indicated more specifically by numeral90 a detailed block diagram of the device controller and data logger.

The external communication interface 9 includes a USB interface and anEthernet interface. The external communication interface 9 connects viaconnection 902 to the Ethernet port 904. The Ethernet 904 port connectsto the Ethernet controller 908 via connection 906. The externalcommunication interface 9 connects via connection 922 to the USB port914. The USB port 914 connects to the USB controller 918 via connection916. The communication controller 922 connects to the Ethernetcontroller 908 via connection 910 and to the USB controller viaconnection 920. The state machine 930 connects to the communicationcontroller 922 via connection 924. The state machine 930 connects to thepower-on reset generator 934 via connection 932. The state machine 930connects to the internal data bus interface 946 via the multi-bitcontrol bus 936, via the multi-bit address bus 938 and via the multi-bitdata bus 940. The state machine 930 connects to the stimulationescalation array loader 928 via the multi-bit control bus 936, via themulti-bit address bus 938 and via the multi-bit data bus 940. The statemachine 930 connects to the real-time-clock 926 via the multi-bitcontrol bus 936, via the multi-bit address bus 938 and via the multi-bitdata bus 940. The state machine 930 connects to the device registermemory 942 via the multi-bit control bus 936, via the multi-bit addressbus 938 and via the multi-bit data bus 940. The state machine 930connects to the stimulation sequence array loader 944 via the multi-bitcontrol bus 936, via the multi-bit address bus 938 and via the multi-bitdata bus 940. The internal data bus interface 946 communicates to allother bus-interfacing registers of the closed loop neuromodulatorthrough the 8-bit parallel control bus 92.

In one embodiment, a device controller and data logger for a closed loopneuromodulator includes a communication controller, a state machine, aninternal data bus interface, a real time clock, an escalation registerarray loader, a sequence register array loader, and a device registermemory. In another embodiment, the communication controller is adaptedto connect to a remote terminal via a USB or Ethernet connection. Inanother embodiment, the device controller further includes a power-onreset generator. In still another embodiment, the device controller isin communication with a closed loop neuromodulator via an internalcontrol bus connected to the internal data bus interface.

Auto-Adjusting, Optimization and Dosing

Start with lowest possible stimuli and increase towards optimum and notstarting with highest possible stimuli and decrease towards optimumbecause highest possible stimuli will generate an arousal of the CNS.

Ideally, the ratio of stimuli generated to airflow-detected occurrencesis above 2 to 1. The rationale for this is that the first stimuli signalshould not generate any arousal so that it is established that thesignal level is low enough as neither to change the sleeping patientssleep state nor to awake him. Then with that base stimuli levelestablished, the next stimuli level generated should be high enough tocause and arousal in order to cause resumption of breathing. Since thefirst level was not high enough to cause any cortical arousal and thesecond level was just slightly above the first level, one can safelyassume that the second level was not strong enough to neither change thesleeping patients sleep state nor wake him up completely. This deviceautomatically figures out both levels.

Patient setup during a first use includes measuring and setting anactual and optimal level of stimulation for each individual patientautomatically during first use, then storing the associated parametersin a setup register.

Making sure that the individual patient responds to the applied stimuliwithin the predetermined time.

Self Optimizing includes constantly measuring the ratio between appliedstimuli and non-breathing events to make sure that the patient changesneither sleep state nor wakes up due to over stimulation. Furthermoremaking sure that the patient does not remain in an apnea state due tounder stimulation

Latch in third to the last stimuli gain setting before the resumption ofbreathing and start there, as the next first stimuli level for the nextno breathing episode.

Escalation steps change from soft to mild to moderate to strong thenharsh.

Record in memory the last gain setting that caused the resumption ofbreathing.

Typically, stimuli type optimization is performed in a clinic on adiagnostic level. The method of stimuli type selection in the apparatusis for the benefit of the sleep practitioner and clinical researcher sothat the optimum stimuli or sequence of stimuli for the desired responsecan be selected.

CNS respiration resumption delay is the time difference between stimulidetection to resumption of breathing.

CNS stimulus detection delay is the time difference between stimulistarted to arousal.

A detailed description of the Method for Dosage Optimization is providedbelow and in a separately filed U.S. Provisional Patent Applicationtitled Method for Dosage Optimization in a closed loop neuromodulator,filed on Aug. 22, 2008, the contents of which are hereby incorporated byreference herein.

Stimulus dosage optimization is about constantly monitoring the effectthat the presently applied stimulus has on the sleeping patient's CNSand subsequently appropriately adjusting the next stimulus in order toachieve the optimal transfer of energy into the CNS for the sleepingpatient at the time when the patient requires apnea therapy withoutwaking the patient or significantly changing the sleep state of thepatient.

Patient setup is about learning what the initial stimulus parameters arethat result in an optimal transfer of energy into the sleeping patient'sCNS.

For the nonprofessionals, the escalation steps change from soft to mildto moderate to strong then harsh.

The method may be used in conjunction with a central nervous systemstimulation controller such as that described herein.

Additionally, the method may be applied while using a transducer such asthat described in the U.S. Provisional Patent Application titledAgitator to Stimulate the Central Nervous System filed on May 2, 2008,with Ser. No. 61/049,802, the contents of which are hereby incorporatedby reference herein.

Additional U.S. patents hereby incorporated by reference herein include:

Inven- Dymedix Patents Granted U.S. Pat. No. tor(s) Breath SensingApparatus 5,311,875 Stasz et al. Electronic Temperature/PressureTransducer D410.584 Stasz et al. Electronic Temperature/PressureTransducer D417.161 Stasz et al. Pyro/Piezo Sensor 6,254,545 Stasz etal. Pyro/Piezo Sensor with Enhanced Sound Response 6,485,432 Stasz etal. Pyro/Piezo Sensor 6,491,642 Stasz Snore Sensor 6,551,256 Stasz etal. Signal Processing Circuit for Pyro/Piezo Transducer 6,702,755 Staszet al. Nasal Vibration Transducer 6,894,427 Alfini

A patient setup is performed during a first application of stimuli.During the first time use, a closed loop neuromodulator performs apatient setup for patient assessment.

During a first application of stimuli during a first use of the closedloop neuromodulator, the controller starts with the stimulus parameterdefault settings as stored in the closed loop neuromodulator memory anddefined by an attending sleep practitioner and related to the outcome ofclinical studies on the patient.

During patient setup, the modulator starts with the lowest energystimulus and moves towards an optimum selection and setting of stimulusparameters.

During patient setup, the closed loop neuromodulator detects, andrecords the actual stimulation for each individual patient automaticallyduring first use.

During stimulus level patient setup, the closed loop neuromodulatorrecords and stores the stimulus level value that caused the resumptionof normal breathing as a marker. During the next apnea episode, theclosed loop neuromodulator uses the stored stimulus level marker andstarts the first stimulus level either one or more stimulus levels belowthe first stimulus level marker value.

During stimulus duration patient setup, the closed loop neuromodulatorrecords and stores the stimulus duration value that caused theresumption of normal breathing as a marker. During the next apneaepisode, the closed loop neuromodulator uses the stored stimulusduration marker and starts the first stimulus level either one or morestimulus levels below the first stimulus duration marker value.

During stimulus rate patient setup, the closed loop neuromodulatorrecords and stores the stimulus rate value that caused the resumption ofnormal breathing as a marker. During the next apnea episode, the closedloop neuromodulator uses the stored stimulus rate marker and starts thefirst stimulus level either one or more stimulus levels below the firststimulus rate marker value.

During stimulus type patient setup, the closed loop neuromodulatorrecords and stores the stimulus type value that caused the resumption ofnormal breathing as a marker. During the next apnea episode, the closedloop neuromodulator uses the stored stimulus type marker and starts thefirst stimulus level either one or more stimulus levels below the firststimulus type marker value.

Stimulus Dosage Optimization

Ideally, the ratio of stimulus generated to sleep disorder events,including apnea events, is above 2 to 1. The rationale for this is thatthe first stimulus signal should not generate any arousal so that it isestablished that the signal level is low enough as neither to change thesleeping patients sleep state nor to awake him. Then with that basestimulus level established, the next stimulus level generated should behigh enough to cause and arousal in order to cause resumption ofbreathing. Since the first level was not high enough to cause anycortical arousal and the second level was just slightly above the firstlevel, one can safely assume that the second level was not strong enoughto neither change the sleeping patients sleep state nor wake him upcompletely. This device automatically figures out both levels.

Stimulus dosage Optimizing, constantly measures the ratio betweenapplied stimulus and non-breathing events to monitor that the patientchanges neither sleep state nor wakes up due to over stimulation.Furthermore making sure that the patient does not remain in an apneastate due to under stimulation.

During the first stimulus dosage optimization, closed loopneuromodulator continues with the stimulus parameter settings asrecorded and stored during the patient setup.

During stimulus dosage optimization, the closed loop neuromodulatordetects, and records the actual stimulation for each individual patientautomatically during each apnea episode.

During stimulus dosage level optimization, the closed loopneuromodulator recalls the last recorded stimulus level value thatcaused the resumption of normal breathing as a new marker. During thenext apnea episode, the closed loop neuromodulator uses the new storedstimulus level marker and starts the first stimulus level either one ormore stimulus levels below the new stimulus level marker value.

During stimulus dosage duration optimization, the closed loopneuromodulator recalls the last recorded stimulus duration value thatcaused the resumption of normal breathing as a new marker. During thenext apnea episode, the closed loop neuromodulator uses the new storedstimulus duration marker and starts the first stimulus level either oneor more stimulus levels below the new stimulus duration marker value.

During stimulus dosage rate optimization, the closed loop neuromodulatorrecalls the last recorded stimulus rate value that caused the resumptionof normal breathing as a new marker. During the next apnea episode, theclosed loop neuromodulator uses the new stored stimulus rate marker andstarts the first stimulus level either one or more stimulus levels belowthe new stimulus rate marker value.

During stimulus dosage type optimization, the closed loop neuromodulatorrecalls the last recorded stimulus type value that caused the resumptionof normal breathing as a new marker. During the next apnea episode, theclosed loop neuromodulator uses the new stored stimulus type marker andstarts the first stimulus level either one or more stimulus levels belowthe new stimulus type marker value.

Referring to FIG. 19, there is indicated more specifically by numeral 1a sleeping patient. The sleeping patient 1 comprises the followingelements, a human Central Nervous System (CNS) 1901, a human respiratoryCNS pathway 1902 connecting the human CNS 1901 to a respiratory system1903. The respiratory system 1903 provided a pathway 1904, in this case,human respiration providing airflow to the patient's nose or mouth 1905.The patient's respiratory airflow 1906 is blown across an airflow sensor2 (for example, but not limited to the one taught in the STASZ U.S. Pat.No. 6,254,545 etc). The airflow sensor 2 connects to the closed loopneuromodulator 4 via a sensor wire pair 3. The closed loopneuromodulator 4 comprises the following elements, an activity tovoltage conversion 1907, which connects via connection 1908 to the inputof the closed loop neuromodulator process 1909, closed loopneuromodulator process 1909 connects via connection 1910 to the input ofthe voltage to stimulus conversion 1911. The output of the voltage tostimulus conversion 1911 connects via wire connection 5 to the stimulustransducer 6. Stimulus transducer 6 delivers the closed loopneuromodulator generated stimulus via the biological connection 1912, toone or more of the patient's five senses (taste, smell, touch, sightand/or sound) in this case a sound transducer connected to the patient'souter ear 1913. The patient's outer ear 1913 connects via the patient'sinner ear 1914 to the human peripheral nervous system (PNS) 1915. Thehuman peripheral nervous system 1915 connects via the auditory nerve1916 to the human central nervous system 1901.

Referring to FIG. 13A, there is indicated more specifically by numeral2000 the stimulus parameters. First, the stimulus sequence 2002 isselected then optimized. Second, the stimulus type 2004 is selected thenoptimized. Third, the stimulus type 2004 is selected then optimized.Fourth, the stimulus duration 2008 is selected then optimized. Fifth,the stimulus rate 2010 is selected then optimized. Sixth, the stimulusescalation 2012 is selected then optimized. The cycle completes andcontinues. This figure points out that this invention makes use of thoseelements and that this invention is referring to them in thedescriptions below. Additionally, as sleep therapy is delivered to apatient and modulated to treat sleep disorder events, in variousexamples, the closed loop neural modulator changes the stimulus to avoidhabituation of the patient to a particular form of stimuli.Anti-habituating sleep therapy, in such embodiments, modulatesanti-habituating sleep therapy elements 2013 including stimulussequence, stimulus type, or combinations thereof, to prevent patienthabituation. In one example, anti-habituating sleep therapy monitorsaverage energy levels of delivered therapy stimuli and modulates thetherapy to avoid habituation if the average energy exceeds a threshold.In some examples, therapy is modulated after a predetermined timeinterval to avoid habituation. It is understood that otheranti-habituating sleep therapy methods are possible without departingfrom the scope of the present subject matter.

Referring to FIG. 13B, there is indicated more specifically by numeral2020 a diagram of general stimulation timing. There is indicated byroman numeral I. an activity signal of a closed loop neuromodulator. Theactivity signal is represented by a logic level signal. The logic levelsmay take on either a logic high state (“1”) or a logic low state (“0”).The high state indicates “normal breathing” which means that the patientis not currently experiencing a breathing disorder. The low stateindicates “Apnea” which means that the patient is currently experiencinga breathing disorder. There is indicated by Roman numeral II. a driversignal of a closed loop neuromodulator. The driver signal is representedby an analog level signal. The analog levels may take on any level valuebetween a lowest level and a highest level. The lowest and the highestlevel are determined by the specific embodiment of the apparatus. Theabsence of a signal indicates “no stimulation”. No stimulation meansthat the patient is currently not subjected to a CNS stimulus signal.The presence of a signal indicates “stimulation”. Stimulation means thatthe patient is currently subjected to a CNS stimulus signal. Letter Aindicates the falling edge of the activity signal indicating a changefrom the patient normal breathing level to the apnea level. In responseto the activity signal going low, the apparatus inserts a stimulationdelay lasting from letter A to letter B to allow for internal processingdelays and internal device set-up times. Letter B indicates the start ofthe actual stimulus driver signal as it is being sent to the patient.Letter C indicates the point where the patient's central nervous systemdetects the presence of the stimulus signal. At this time the stimuluscould stop, however, the apparatus has no knowledge or information thatthe patient just detected the stimulus signal, thus the stimulus signalcontinues for another duration that is indicated as the excessstimulation. It is also a goal of this invention to minimize the excessstimulation duration in order to minimize over stimulation throughexcess stimulus duration. Letter D indicates the end of the stimulussignal as it is being sent to the patient. The time between C and E isthe time it takes the patient's CNS to detect, realize and act upon thereceived stimulus. In this case, the detection of the stimulus at pointC is triggering the resumption of breathing at point E. The time betweenA and B is the apparatus internal stimulation delay. The time between Band D is the apparatus controlled stimulation duration. The time betweenD and E is the time between the end of stimulation till the time ofrespiration resumption. The time between B and C is patient dependentand represents the CNS stimulus detection delay. The time between C andE is patient dependent and represent the CNS respiration resumptiondelay.

Referring to FIG. 14A, there is indicated more specifically by numeral2030 a diagram of a stimulation optimization, more specifically thesituation of patient CNS overstimulation. There is indicated by Romannumeral I. an activity signal of a closed loop neuromodulator. Theactivity signal is represented by a logic level signal. The logic levelsmay take on either a logic high state (“1”) or a logic low state (“0”).The high state indicates “normal breathing” which means that the patientis not currently experiencing a breathing disorder. The low stateindicates “Apnea” which means that the patient is currently experiencinga breathing disorder. There is indicated by Roman numeral II. a driversignal of a closed loop neuromodulator. The driver signal is representedby an analog level signal #1. The analog levels may take on any levelvalue between a lowest level and a highest level. The lowest and thehighest level are determined by the specific embodiment of theapparatus. The absence of a signal indicates “no stimulation”. Nostimulation means that the patient is currently not subjected to a CNSstimulus signal. The presence of a signal indicates “stimulation”.Stimulation means that the patient is currently subjected to a CNSstimulus signal.

Shortly after the activity signal changes from the normal breathingstate to the apnea state, the driver signal issues a stimulus signal #1.Shortly after the apparatus has issued the stimulus signal #1, theapparatus has issued the activity signal changes state from apnea tonormal breathing, meaning that the patient has started to resume normalrespiration shortly after the first stimulus signal. This is not quite adesirable situation because it is safe to assume that this stimulussignal was simply too strong and it aroused the CNS more dramaticallythan desired and cause the patient most likely to wake up and in alesser case, change sleep states and resume breathing. The key point ofthis invention is to neither wake the patient nor make him or her changesleep states significantly. When the second stimulus after the detectionof an apnea caused this effect than according to this invention, thepatient has been optimally stimulated.

Referring to FIG. 14B, there is indicated more specifically by numeral2040 a diagram of a stimulation optimization, more specifically thesituation of patient optimal CNS stimulation. There is indicated byRoman numeral I. an activity signal of a closed loop neuromodulator. Theactivity signal is represented by a logic level signal. The logic levelsmay take on either a logic high state (“1”) or a logic low state (“0”).The high state indicates “normal breathing” which means that the patientis not currently experiencing a breathing disorder. The low stateindicates “Apnea” which means that the patient is currently experiencinga breathing disorder. There is indicated by Roman numeral II. a driversignal of a closed loop neuromodulator. The driver signal is representedby an analog level signal #1. The analog levels may take on any levelvalue between a lowest level and a highest level. The lowest and thehighest level are determined by the specific embodiment of theapparatus. The absence of a signal indicates “no stimulation”. Nostimulation means that the patient is currently not subjected to a CNSstimulus signal. The presence of a signal indicates “stimulation”.Stimulation means that the patient is currently subjected to a CNSstimulus signal.

Shortly after the activity signal changes from the normal breathingstate to the apnea state, the driver signal issues a stimulus signal #1.Since after a short while stimulus signal #1 has not caused theresumption of breathing, a second stimulus signal #2 issues. Since thefirst stimulus signal has not caused the respiration to resume, one cansafely assume that the patient neither woke up nor did patient changesleep states, nor did the first stimulus cause a significant CNSarousal. Shortly after the second stimulus signal #2 issues, theactivity signal changes state from apnea to normal breathing, indicatingthat the patient has started to resume normal respiration shortly afterthe second stimulus signal has been issued by the apparatus. This is adesirable situation because it is safe to assume that the secondstimulus was of adequate strength to cause the patient to breathe again.Is also safe to assume since the first stimulus signal was not strongenough to cause the resumption of breathing and neither woke the patientnor caused the patient to change sleep state, that the second stimulus,which was just slightly stronger, did also not wake nor significantlychanged the patients sleep states. The second stimulus #2 was dosedoptimally in order to cause the patient to resume breathing after thefirst stimulus showed no effect. The key point of this invention is toneither wake nor make the patient change sleep states significantly.When the second stimulus after the detection of an apnea caused thiseffect than according to this invention, the patient has been optimallystimulated.

Referring to FIG. 14C, there is indicated more specifically by numeral2050 a diagram of a CNS stimulation optimization, more specifically thesituation of patient CNS under stimulation. There is indicated by Romannumeral I. an activity signal of a closed loop neuromodulator. Theactivity signal is represented by a logic level signal. The logic levelsmay take on either a logic high state (“1”) or a logic low state (“0”).The high state indicates “normal breathing” which means that the patientis not currently experiencing a breathing disorder. The low stateindicates “Apnea” which means that the patient is currently experiencinga breathing disorder. There is indicated by Roman numeral II. a driversignal of a closed loop neuromodulator. The driver signal is representedby an analog level signal #1. The analog levels may take on any levelvalue between a lowest level and a highest level. The lowest and thehighest level are determined by the specific embodiment of theapparatus. The absence of a signal indicates “no stimulation”. Nostimulation means that the patient is currently not subjected to a CNSstimulus signal. The presence of a signal indicates “stimulation”.Stimulation means that the patient is currently subjected to a CNSstimulus signal.

Shortly after the activity signal changes from the normal breathingstate to the apnea state, the driver signal issues a stimulus signal #1.Since after a short while stimulus signal #1 has not caused theresumption of breathing, a second stimulus signal #2 issues. Since thefirst stimulus signal has not caused the respiration to resume, one cansafely assume that the patient neither woke up nor did patient changesleep states, nor did the first stimulus cause a significant CNSarousal.

Shortly after the second stimulus signal #2 issues, the activity signalstill does not change state from apnea to normal breathing, indicatingthat the patient has not yet started to resume normal respirationshortly after the second stimulus signal has been issued by theapparatus. This is also not a desirable situation because it has notcaused the patient to resume breathing. It is safe to assume that thesecond stimulus was also not of adequate strength to cause the patientto breathe again. It is also safe to assume since the first stimulussignal was not strong enough to cause the resumption of breathing andneither woke the patient nor caused the patient to change sleep state,that the second stimulus, which was just slightly stronger, did also notwake nor significantly changed the patients sleep states.

The third stimulus #3 was dosed properly but not optimally, even thoughit caused the patient to resume. The key point of this invention is toneither wake nor make the patient change sleep states significantly butcause the speedy safe resumption of breathing soon after an apnea eventhas been detected. When the third stimulus after the detection of anapnea caused the patient to breathe than according to this invention,the patient has been under stimulated.

A goal of this invention to attempt to maintain an optimal stimulusdosage, which neither wakes the patient nor causes the patient to changesleep states and to optimally dose the individual stimulus accordingly.The method employed to obtain this goal is to constantly monitor andkeep track of the effectiveness of patient stimulation. If the patientresumes breathing after the first stimulus then the next time thepatient experiences an apnea, the first stimulus will be issued withsignificantly less strength. Strength is defined as the amount of energycontained within the applied stimulus. A first stimulus withsignificantly reduced strength should not cause the patient to resumebreathing because this would indicate that the stimulus was strongenough to cause so much CNS stimulation that the patient either woke upor the patient experienced a significant change in sleep state. Thismethod is being repeated until the first stimulus issued after thedetection of an apnea does not cause the resumption of breathing in apatient. It can thus be safely assumed that if the second stimulus isjust slightly higher and causes the resumption of breathing that thesecond stimulus was dosed optimally. Furthermore, that if the secondstimulus does neither cause resumption of breathing and that the thirdstimulus which is also slightly stronger than the third causes theresumption of breathing, that the first stimulus issued shortly afterthe next detection of an apnea is less in strength than the thirdstimulus that was applied in the previous apnea.

Referring to FIG. 15A, there is indicated more specifically by numeral2060 a diagram of a CNS stimulation application.

There is indicated by Roman numeral I. an activity signal of a closedloop neuromodulator. The activity signal is represented by a logic levelsignal. The logic levels may take on either a logic high state (“1”) ora logic low state (“0”). The high state indicates “normal breathing”which means that the patient is not currently experiencing a breathingdisorder. The low state indicates “Apnea” which means that the patientis currently experiencing a breathing disorder.

There is indicated by Roman numeral II. a stimulus rate signal of aclosed loop neuromodulator. The stimulus rate signal is represented by alogic level signal. The logic levels may take on either a logic highstate (“1”) or a logic low state (“0”). The stimulation signal rate maybe adjusted either manually by the sleep professional or automaticallyby the apparatus (e.g. as instructed or required by the CNS stimulationoptimization method). Shortly after the activity signal changes from thenormal breathing state to the apnea state, the stimulus rate signalchanges state from a logic low to a logic high after the stimulus delayperiod, which may also be adjusted either manually by the sleepprofessional or automatically by the apparatus (e.g. as instructed orrequired by the CNS stimulation optimization method). The change ofsignal state from low to high of the stimulus rate signal indicates thestart of a stimulus signal. The stimulus rate signal remains active andkeeps on changing states indicating the need for continuously issuingCNS stimulus to the patient until normal breathing has resumed.

There is indicated by Roman numeral III. a stimulus duration signal of aclosed loop neuromodulator. The stimulus duration signal is representedby a logic level signal. The logic levels may take on either a logichigh state (“1”) or a logic low state (“0”). The stimulus duration maybe adjusted by either manually by the sleep professional orautomatically by the apparatus (e.g. as instructed or required by theCNS stimulation optimization method). As soon as the stimulus ratesignal II. changes state from low to high, the stimulus duration signalgoes high (active) for the specific duration of the presently appliedCNS stimulus. The stimulus duration signal remains active and keeps onchanging states indicating the need for continuously issuing CNSstimulus to the patient until normal breathing has resumed.

There is indicated by Roman numeral IV. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal #1. The analog levels may take on any level value between alowest level and a highest level. The CNS stimulation level may beadjusted either manually by the sleep professional or automatically bythe apparatus (e.g. as instructed or required by the CNS stimulationoptimization method). The absence of a signal indicates “nostimulation”. No stimulation means that the patient is currently notsubjected to a CNS stimulus signal. The presence of a signal indicates“stimulation”. Stimulation means that the patient is currently subjectedto a CNS stimulus signal. The first CNS stimulus issued by the driversignal IV. after the activity signal transitions from high to lowindicating an apnea is indicated by numeral #1A. The numeral indicatesthat this is the first (1) stimulus (#) of this apnea of stimulus levelA (A). The selection of which stimulus level is to be issued shortlyafter an apnea has been detected may be may be controlled eithermanually by the sleep professional or automatically by the apparatus(e.g. as instructed or required by the CNS stimulation optimizationmethod). In this case, the stimulus selected is of the lowest level(aka; strength, volume, loudness). After the first stimulus dosage hasbeen issued to the patient's CNS, the apparatus waits for a certain CNSstimulation dwell time that is dependent on the stimulus rate andstimulus duration. After the stimulation dwell time has expired, a newstimulus will be issued unless the activity signal transitions from lowto high indicating that normal breathing has resumed and that no morestimulus are required.

If normal breathing has not resumed after issuing first stimulus #1Athen the apparatus may issue second stimulus #2B of stimulus level B.According to this invention, this stimulus may be of a different type,may be of a different level, may be of a different rate, or may be of adifferent duration. In this example, only a different level isindicated. A higher stimulus level delivers more energy into the CNS andit is assumed that a higher stimulus level causes a stronger responsefrom the CNS. It is hoped in this case that following the arousal of thepatient's CNS by the detection of the presently applied stimulus willcause the resumption of breathing.

If normal breathing has not resumed after issuing second stimulus #2Bthen a third the apparatus may issue stimulus #3C of stimulus level C.The apparatus will again monitor for the resumption of the desiredpatient activity or the cessation of the undesired patient activity.

If normal breathing has not resumed after issuing third stimulus #3Cthen a fourth stimulus #4D of stimulus level the apparatus may issue D.The apparatus constantly monitors for the resumption of the desiredpatient activity or the cessation of the undesired patient activity.

In this case, CNS stimulus #4D was successful in causing the resumptionof the patient's desired activity (breathing) indicated by the low tohigh transition of the activity signal.

After the patient has resumed the desired activity/normal, breathing theapparatus will issue no further CNS stimulus until the activity signaltransitions from high to low again indicating a detection of a sleepapnea or any other undesired behavior that can be controlled bycontrolled stimulation of the CNS.

Referring to FIG. 15B, there is indicated more specifically by numeral2070 a diagram of a CNS stimulus escalation method.

There is indicated by Roman numeral I. an activity signal of a closedloop neuromodulator. The activity signal is represented by a logic levelsignal. The logic levels may take on either a logic high state (“1”) ora logic low state (“0”). The high state indicates “normal breathing”which means that the patient is not currently experiencing a breathingdisorder. The low state indicates “Apnea” which means that the patientis currently experiencing a breathing disorder.

There is indicated by Roman numeral II. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to apneadetection is #1A. Stimulus #1A may be of any type, level, duration orrate. If stimulus #1A does not cause the resumption of normal breathingthen after a certain amount of time that is dependent on the specificstimulus rate, second stimulus #2B is being issued. Since the firststimulus #1A did not produce the desire result, the level for stimulus#2B has been increased by a specific amount, which depends on the typeof level escalation envelope function. In this case, the levelescalation envelope function is linear. This means the each nextstimulus level increases with the same factor as the one before. Otherlevel stimulus escalation envelope functions are possible as discussedin the Stimulus Escalator section included herein. If stimulus #2B doesnot cause the resumption of normal breathing then after a certain amountof time that is dependent on the specific stimulus rate, a thirdstimulus #3C is being issued. Since the second stimulus #2B did notproduce the desire result, the level for stimulus #3C has been increasedby a specific amount, which depends on the type of level escalationenvelope function. If stimulus #3C does not cause the resumption ofnormal breathing then after a certain amount of time that is dependenton the specific stimulus rate, a fourth stimulus #4D is being issued.Since the third stimulus #3C did not produce the desire result, thelevel for stimulus #4D has been increased by a specific amount whichdepends on the type of level escalation envelope function. This patternof issuing ever changing and increasing stimulus types, levels,durations and rates continues until normal breathing has been detected.

There is indicated by Roman numeral III. a driver signal of a closedloop neuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to apneadetection is #1A′. Stimulus #1A′ may be of any type, level, duration orrate and stimulus #1A′ does not have to be the same as stimulus #1A. Ifstimulus #1A′ does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a second stimulus #2A″ is being issued. Since the firststimulus #1A′ did not produce the desire result, the type, duration orrate for stimulus #2A″ has been changed by a specific amount whichdepends on the type of level escalation envelope function, however, thelevel has not been increased this time. Either in this case theescalation envelope function is defined as a type, duration or ratechange and the envelope function may be linear or take on any othermathematical function including a randomization. This means the eachnext stimulus is different from the one before. Other stimulusescalation envelope functions are possible as discussed in the StimulusEscalator section and the Stimulus Sequencer section included herein. Ifstimulus #2A″ does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a third stimulus #3B′ is being issued. Since the secondstimulus #2A″ did not produce the desire result, the type, duration orrate for stimulus #3B′ has been changed by a specific amount whichdepends on the type of escalation envelope function. If stimulus #3B′does not cause the resumption of normal breathing then after a certainamount of time that is dependent on the specific stimulus rate, a fourthstimulus #4B″ is being issued. Since the third stimulus #3B′ did notproduce the desired result, the level for stimulus #4B″ has beenincreased by a specific amount which depends on the type of escalationenvelope function. This pattern of issuing ever changing and increasingstimulus types, levels, durations and rates continues until normalbreathing has been detected. It shall be noted that the same level hasbeen repeated twice in this sequence of stimulus delivery.

There is indicated by Roman numeral IV. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to an apneadetection is #1A′″. Stimulus #1A′″ may be of any type, level, durationor rate. If stimulus #1A′″ does not cause the resumption of normalbreathing then after a certain amount of time that is dependent on thespecific stimulus rate, a second stimulus #2A″″ is being issued. Sincethe first stimulus #1A′″ did not produce the desire result, the type,duration or rate for stimulus #2A″″ has been changed by a specificamount which depends on the type of level escalation envelope function,however, the level has not been increased this time. Either in this casethe escalation envelope function is defined as a type, duration or ratechange and the envelope function may be linear or take on any othermathematical function including a randomization. This means the eachnext stimulus is different from the one before. Other stimulusescalation envelope functions are possible as discussed in the StimulusEscalator section included herein. If stimulus #2A″″ does not cause theresumption of normal breathing then after a certain amount of time thatis dependent on the specific stimulus rate, a third stimulus #3A′″″ isbeing issued. Since the second stimulus #2A″″ did not produce the desireresult, the type, duration or rate for stimulus #3A′″″ has been changedby a specific amount, which depends on the type of escalation envelopefunction. If stimulus #3A′″″ does not cause the resumption of normalbreathing then after a certain amount of time that is dependent on thespecific stimulus rate, a fourth stimulus #4B′″ is being issued. Sincethe third stimulus #3A′″″ did not produce the desired result, the levelfor stimulus #4B′″ has been increased by a specific amount which dependson the type of escalation envelope function. This pattern of issuingever changing and increasing stimulus types, levels, durations and ratescontinues until normal breathing has been detected. It shall be notedthat the same level has been repeated three times in this sequence ofstimulus delivery.

Referring to FIG. 16A, there is indicated more specifically by numeral2080 a diagram of a CNS stimulus level optimization method.

There is indicated by Roman numeral I. an activity signal of a closedloop neuromodulator depicting non-optimized apnea duration at timeinterval T. The activity signal is represented by a logic level signal.The logic levels may take on either a logic high state (“1”) or a logiclow state (“0”). The high state indicates “normal breathing” which meansthat the patient is not currently experiencing a breathing disorder. Thelow state indicates “Apnea” which means that the patient is currentlyexperiencing a breathing disorder.

There is indicated by Roman numeral II. A driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to apneadetection is the lowest stimulus level possible #1A. Stimulus #1A may beof any type, duration or rate. If stimulus #1A does not cause theresumption of normal breathing then after a certain amount of time thatis dependent on the specific stimulus rate, second stimulus #2B is beingissued. Since the first stimulus #1A did not produce the desired result,the level for stimulus #2B has been increased by a specific amount,which depends on the type of level escalation envelope function. In thiscase, for sake of simplicity, the level escalation envelope function hasbeen chosen to be linear. This means the next stimulus level increaseswith the same factor as the one before. Other level stimulus escalationenvelope functions are possible as discussed in the Stimulus Escalatorsection included herein. If stimulus #2B does not cause the resumptionof normal breathing then after a certain amount of time that isdependent on the specific stimulus rate, a third stimulus #3C is beingissued. Since the second stimulus #2B did not produce the desire result,the level for stimulus #3C has been increased by a specific amount,which depends on the type of level escalation envelope function.

If stimulus #3C does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fourth stimulus #4D is being issued. Since the thirdstimulus #3C did not produce the desire result, the level for stimulus#4D has been increased by a specific amount which depends on the type oflevel escalation envelope function.

If stimulus #4D does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fifth stimulus #5E is being issued. Since the fourthstimulus #4D did not produce the desire result, the level for stimulus#5E has been increased by a specific amount, which depends on the typeof level escalation envelope function.

If stimulus #5E does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a sixth stimulus #6F is being issued. Since the fifthstimulus #5E did not produce the desire result, the level for stimulus#6F has been increased by a specific amount, which depends on the typeof level escalation envelope function.

If stimulus #6F does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a seventh stimulus #7G is being issued. Since the sixthstimulus #6F did not produce the desire result, the level for stimulus#7G has been increased by a specific amount which depends on the type oflevel escalation envelope function.

It shall be noted that the seventh stimulus in this case #7G has causedthe resumption of normal breathing in the sleeping patient. At thispoint, the method instructs the apparatus to store the value of thelevel that caused the resumption of breathing in memory. This valueshall be used as a marker so that the first stimulus level the closedloop neuromodulator selects and issues after detection of the next apneaepisode is at least one or more escalation levels below the level thatcaused the resumption of breathing during the previous apnea episodeexperienced by the patient. In this special case stimulus level #G wasthe one that caused the resumption of normal breathing, thus the firstlevel that shall be issued when the next apnea episode occurs isstimulus level #E.

There is indicated by Roman numeral III. an activity signal of a closedloop neuromodulator depicting an optimized apnea duration at timeinterval T+1 indicating the next apnea episode following the apneaepisode duration at the time interval T. The activity signal isrepresented by a logic level signal. The logic levels may take on eithera logic high state (“1”) or a logic low state (“0”). The high stateindicates “normal breathing” which means that the patient is notcurrently experiencing a breathing disorder. The low state indicates“Apnea” which means that the patient is currently experiencing abreathing disorder.

There is indicated by Roman numeral VI. A driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to the nextapnea detection is the third level down from the level during theprevious apnea that caused the resumption of normal breathing in thesleeping patient stimulus level #1E. Stimulus #1E is preferably of thesame type, duration or rate but may be of any type, duration or rate. Ifstimulus #1E does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a second stimulus #2F is being issued. Since the firststimulus #1E did not produce the desired result, the level for stimulus#2F has been increased by a specific amount, which depends on the typeof level escalation envelope function. In this case, for sake ofsimplicity, the level escalation envelope function has been chosen to belinear. This means the next stimulus level increases with the samefactor as the one before. Other level stimulus escalation envelopefunctions are possible as discussed in the Stimulus Escalator sectionincluded herein. If stimulus #2F does not cause the resumption of normalbreathing then after a certain amount of time that is dependent on thespecific stimulus rate, a third stimulus #3G is being issued. Since thesecond stimulus #2F did not produce the desire result, the level forstimulus #3G has been increased by a specific amount which depends onthe type of level escalation envelope function.

It shall be noted that the third stimulus this time #3G has caused theresumption of normal breathing in the sleeping patient. At this point,again, the method instructs the apparatus to store the value of thelevel that caused the resumption of breathing in memory. This valueshall be used as a marker so that the first stimulus level the closedloop neuromodulator selects and issues after detection of the next apneaepisode is at least one or more escalation levels below the level thatcaused the resumption of breathing during the previous apnea episodeexperienced by the patient. In this special case stimulus level #G wasthe one that caused the resumption of normal breathing, thus the firstlevel that shall be issued when the next apnea episode occurs isstimulus level #E.

The method changing stimuli and patterns of issuing more energycontaining stimulus types, levels, durations and rates continues untilnormal breathing has been detected.

Referring to FIG. 16B, there is indicated more specifically by numeral2090 a diagram of a CNS stimulus duration optimization method.

There is indicated by Roman numeral I. an activity signal of a closedloop neuromodulator depicting non-optimized apnea duration at timeinterval T. The activity signal is represented by a logic level signal.The logic levels may take on either a logic high state (“1”) or a logiclow state (“0”). The high state indicates “normal breathing” which meansthat the patient is not currently experiencing a breathing disorder. Thelow state indicates “Apnea” which means that the patient is currentlyexperiencing a breathing disorder.

There is indicated by Roman numeral II. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to apneadetection is the shortest stimulus duration possible #1A. Stimulus #1Amay be of any type, level or rate. If stimulus #1A does not cause theresumption of normal breathing, then after a certain amount of time thatis dependent on the specific stimulus rate, second stimulus #2B is beingissued. Since the first stimulus #1A did not produce the desired result,the duration (more duration equals more energy) for stimulus #2B hasbeen increased by a specific amount which depends on the type ofduration escalation envelope function. In this case, for sake ofsimplicity, the duration escalation envelope function has been chosen tobe linear. This means the next stimulus duration increases with the samefactor as the one before. Other duration stimulus escalation envelopefunctions are possible as discussed in the Stimulus Escalator sectionincluded herein. If stimulus #2B does not cause the resumption of normalbreathing then after a certain amount of time that is dependent on thespecific stimulus rate, a third stimulus #3C is being issued. Since thesecond stimulus #2B did not produce the desired result, the duration forstimulus #3C has been increased by a specific amount, which depends onthe type of duration escalation envelope function.

If stimulus #3C does not caused the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fourth stimulus #4D is being issued. Since the thirdstimulus #3C did not produce the desired result, the duration forstimulus #4D has been increased by a specific amount, which depends onthe type of duration escalation envelope function.

If stimulus #4D does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fifth stimulus #5E is being issued. Since the fourthstimulus #4D did not produce the desire result, the duration forstimulus #5E has been increased by a specific amount, which depends onthe type of duration escalation envelope function.

It shall be noted that the fifth stimulus in this case #5E has causedthe resumption of normal breathing in the sleeping patient. At thispoint, the method instructs the apparatus to store the value of theduration that caused the resumption of breathing in memory. This valueshall be used as a marker so that the first stimulus duration the closedloop neuromodulator selects and issues after detection of the next apneaepisode is at least one or more escalation durations below the durationthat caused the resumption of breathing during the previous apneaepisode experienced by the patient. In this special case duration level#E was the one that caused the resumption of normal breathing, thus thefirst stimulus duration that shall be issued when the next apnea episodeoccurs is stimulus level #D.

There is indicated by Roman numeral III. an activity signal of a closedloop neuromodulator depicting an optimized apnea duration at timeinterval T+1 indicating the next apnea episode following the apneaepisode duration at the time interval T. The activity signal isrepresented by a logic level signal. The logic levels may take on eithera logic high state (“1”) or a logic low state (“0”). The high stateindicates “normal breathing” which means that the patient is notcurrently experiencing a breathing disorder. The low state indicates“Apnea” which means that the patient is currently experiencing abreathing disorder.

There is indicated by Roman numeral VI. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog durations may take on any duration value ifinstructed to do so between a lowest duration and a highest duration. Inthis case, the first stimulus being issued after a short delay inresponse to the next apnea detection is the third duration down from theduration during the previous apnea that caused the resumption of normalbreathing in the sleeping patient stimulus duration #1D. Stimulus #1D ispreferably of the same type, level and/or rate but may be of any type,level and/or rate. If stimulus #1D does not cause the resumption ofnormal breathing then after a certain amount of time that is dependenton the specific stimulus rate, second stimulus #2E is being issued.Since the first stimulus #1D did not produce the desired result, theduration for stimulus #2E has been increased by a specific amount, whichdepends on the type of duration escalation envelope function. In thiscase, for sake of simplicity, the duration escalation envelope functionhas been chosen to be linear. This means the next stimulus durationincreases with the same factor as the one before. Other durationstimulus escalation envelope functions are possible as discussed in theStimulus Escalator section included herein.

It shall be noted that the second stimulus this time #2E has caused theresumption of normal breathing in the sleeping patient. At this point,again, the method instructs the apparatus to store the value of thestimulus duration that caused the resumption of breathing in memory.This value shall be used as a marker so that the first stimulus durationthe closed loop neuromodulator selects and issues after detection of thenext apnea episode is at least one or more escalation durations belowthe duration that caused the resumption of breathing during the previousapnea episode experienced by the patient. In this special case stimulusduration #E was the one that caused the resumption of normal breathing,thus the first duration that shall be issued when the next apnea episodeoccurs is stimulus duration #D, because the escalation resumption pointhas been set to one level down in this case.

The method changing stimuli and patterns of issuing more energycontaining stimulus types, levels, durations and rates continues untilnormal breathing has been detected.

Referring to FIG. 16C, there is indicated more specifically by numeral2100 a diagram of a CNS stimulus rate optimization method.

There is indicated by Roman numeral I. an activity signal of a closedloop neuromodulator depicting non-optimized apnea duration at timeinterval T. The activity signal is represented by a logic level signal.The logic levels may take on either a logic high state (“1”) or a logiclow state (“0”). The high state indicates “normal breathing” which meansthat the patient is not currently experiencing a breathing disorder. Thelow state indicates “Apnea” which means that the patient is currentlyexperiencing a breathing disorder.

There is indicated by Roman numeral II. A driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to an apneadetection is the lowest stimulus rate possible (as defined in thedefault settings) #1A. Stimulus #1A may be of any type, duration orlevel. If stimulus #1A does not cause the resumption of normal breathingthen after a certain amount of time that is dependent on the specificstimulus rate, second stimulus #2B is being issued. Since the firststimulus #1A did not produce the desired result, the rate for stimulus#2B has been increased (sped up) by a specific amount, which depends onthe type of rate escalation envelope function. In this case, for sake ofsimplicity, the rate escalation envelope function has been chosen to belinear. This means the next stimulus level increases with the samefactor as the one before. Other rate stimulus escalation envelopefunctions are possible as discussed in the Stimulus Escalator sectionincluded herein. If stimulus #2B does not cause the resumption of normalbreathing then after a certain amount of time that is dependent on thespecific stimulus rate, a third stimulus #3C is being issued. Since thesecond stimulus #2B did not produce the desire result, the rate forstimulus #3C has been increased by a specific amount, which depends onthe type of rate escalation envelope function.

If stimulus #3C does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fourth stimulus #4D is being issued. Since the thirdstimulus, #3C did not produce the desire result, the rate for stimulus#4D has been increased by a specific amount which depends on the type ofrate escalation envelope function.

If stimulus #4D does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a fifth stimulus #5E is being issued. Since the fourthstimulus #4D did not produce the desire result, the rate for stimulus#5E has been increased by a specific amount which depends on the type ofrate escalation envelope function.

If stimulus #5E does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a sixth stimulus #6F is being issued. Since the fifthstimulus #5E did not produce the desire result, the rate for stimulus#6F has been increased by a specific amount which depends on the type ofrate escalation envelope function.

It shall be noted that the seventh stimulus in this case #6F has causedthe resumption of normal breathing in the sleeping patient. At thispoint, the method instructs the apparatus to store the value of the ratethat caused the resumption of breathing in memory. This value shall beused as a marker so that the first stimulus rate the closed loopneuromodulator selects and issues after detection of the next apneaepisode is at least one or more escalation rates below the rate thatcaused the resumption of breathing during the previous apnea episodeexperienced by the patient. In this special case stimulus rate #F wasthe one that caused the resumption of normal breathing, thus the firstrate that shall be issued when the next apnea episode occurs is stimulusrate #D.

There is indicated by Roman numeral III. an activity signal of a closedloop neuromodulator depicting an optimized apnea duration at timeinterval T+1 indicating the next apnea episode following the apneaepisode duration at the time interval T. The activity signal isrepresented by a logic level signal. The logic levels may take on eithera logic high state (“1”) or a logic low state (“0”). The high stateindicates “normal breathing” which means that the patient is notcurrently experiencing a breathing disorder. The low state indicates“Apnea” which means that the patient is currently experiencing abreathing disorder.

There is indicated by Roman numeral VI. a driver signal of a closed loopneuromodulator. The driver signal is represented by an analog levelsignal. The analog levels may take on any level value if instructed todo so between a lowest level and a highest level. In this case, thefirst stimulus being issued after a short delay in response to the nextapnea detection is the third rate down from the rate during the previousapnea that caused the resumption of normal breathing in the sleepingpatient stimulus rate #1D. Stimulus #1D is preferably of the same type,duration and/or level but may be of any type, duration or level. Ifstimulus #1D does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, second stimulus #2E is being issued. Since the firststimulus #1D did not produce the desired result, the rate for stimulus#2E has been increased by a specific amount, which depends on the typeof rate escalation envelope function. In this case, for sake ofsimplicity, the rate escalation envelope function has been chosen to belinear. This means the next stimulus rate increases with the same factoras the one before. Other rate stimulus escalation envelope functions arepossible as discussed in the Stimulus Escalator section included herein.If stimulus #2E does not cause the resumption of normal breathing thenafter a certain amount of time that is dependent on the specificstimulus rate, a third stimulus #3F is being issued. Since the secondstimulus #2E did not produce the desire result, the rate for stimulus#3F has been increased by a specific amount, which depends on the typeof rate escalation envelope function.

It shall be noted that the third stimulus this time #3F has caused theresumption of normal breathing in the sleeping patient. At this point,again, the method instructs the apparatus to store the value of the ratethat caused the resumption of breathing in memory. This value shall beused as a marker so that the first stimulus rate the closed loopneuromodulator selects and issues after detection of the next apneaepisode is at least one or more escalation rates below the rate thatcaused the resumption of breathing during the previous apnea episodeexperienced by the patient. In this special case stimulus rate #F wasthe one that caused the resumption of normal breathing, thus the firstrate that shall be issued when the next apnea episode occurs is stimulusrate #D.

The method changing stimuli and patterns of issuing more energycontaining stimulus types, levels, durations and rates continues untilnormal breathing has been detected.

Referring to FIG. 17, there is indicated more specifically by numeral2110 a flowchart of stimulus dosage optimization routine for a closedloop neuromodulator. The stimulus dosage optimization routine beginswith the Stimulus Dosage Optimization start command 2112. The next stepafter the start command 2112 is the instruction to load the storedstimulus parameters 2114, which at first may be the default values asdefined by the outcome of clinical trials or as defined by a sleeppractitioner. The next process after loading the stored stimulusparameters is to monitor for Apnea 2116. The next step after monitoringfor an apnea is the decision point which asks for the Next Apnea? 2118.If the answer to the decision point question is NO then the routine willcontinue to monitor for Apnea. If the answer to the decision pointquestion is YES then the next process in the routine is to ApplyStimulus to Patient 2120. During and after the stimulus has been appliedto the patient another decision point asks if the patient is still inApnea? 2122. If the answer to the decision point question is NO then theroutine encounters another decision point, which asks if this was thefirst Stimulus? 2130 in this apnea episode. If the answer to thisdecision point question is YES, then the routine indicates “OverStimulation” 2132, which may be subsequently logged, and time stampedfor further use and reference. The next step after “Over Stimulation”2132 which also means that the first stimulus issued to the patientcaused the resumption of breathing is to decrease the stimulus parameter2134 followed by a Record & Store New Stimulus Parameter 2136instruction. Since the patient is not experiencing an Apnea at thisstate, the next step is to monitor for Apnea 2116. If the patientexperiences another apnea then the answer to the Next Apnea 2118decision point question is YES then the next process in the routine isto Apply Stimulus to Patient 2120. During and after the stimulus hasbeen applied to the patient another decision point asks if the patientis still in Apnea? 2122. If the answer to the decision point question isYES then the routine indicates “Under Stimulation” 2124, which may besubsequently logged, and time stamped for further use and reference. Thenext step after “Under Stimulation” 2124 which also means that thestimulus issued to the patient did not cause the resumption of breathingis to increase the stimulus parameter 2126 followed by a Record & StoreNew Stimulus Parameter 2128 instruction. Since the patient isexperiencing an Apnea at this state, the next step is to Apply Stimulusto the Patient 2120. During and after the stimulus has been applied tothe patient a decision point asks if the patient is still in Apnea <?>2122. If the answer to the decision point question is NO then theroutine encounters another decision point which asks if this was thefirst Stimulus <?> 2130 in this apnea episode. If the answer to thisdecision point question is NO, then the routine indicates “OptimalStimulation” 2138, which may be subsequently logged, and time stampedfor further use and reference. The stimulus dosage optimization routinemay at this point be terminated, re-routed to another routine or startall over again.

Diagnostic and Therapy Modes

There is a need for automatic/autonomous mode, so that the sleep patientcan operate the unit at home without any manual interaction orintervention. In diagnostic mode the sleep lab practitioner can find theoptimum range of stimulus escalation for the individual patient. Invarious examples, diagnostic mode is used in a sleep lab to setup aclosed loop neuromodulator and then the patient is sent home where theclosed loop neuromodulator is used in therapy mode to provide sleeptherapy. In some examples, a sleep lab only uses diagnostic mode of theneuromodulator.

In therapy mode, the unit executes its operation based on the rangesdefined and set by the sleep practitioner.

In therapy mode, the unit is the controller part of a respiratorybiofeedback loop.

Delay, rate, duration, period, frequency, range etc. are all variableand manually adjustable by sleep lab practitioner when this invention isused in diagnostic mode or automatically adjustable when used in therapymode.

Especially ranges or all adjustable parameters are settable by the sleeppractitioner in diagnostic mode.

Therapy mode is automatic and is an autonomous operation.

All timing is variable, adjustable, controllable, either manual orautomatic.

In therapy mode, the unit can operate under minimum power requirementsand highest efficiency, thus, saving battery life and extending time ofoperation. The use of a digital output drive amplifier like a classD-audio amplifiers that are available from semiconductor manufacturerswill allow for efficient use of battery power during the application oftherapy stimuli.

A set of subroutines in the diagnostic remote terminal can makecalculations based on the registers and values provided by the device. Afew examples of such calculations that will give the medicalpractitioner a better patient picture are listed below:

1. Average Breaths per Minute (or any other time reference)

2. Average Inhale duration over Exhale duration ratio

3. Average Apneas per hour (or any other time reference)

4. Average Stimuli per hour

5. Average Stimuli per Apnea

6. Histograms of inhalation count and durations

7. Histograms of exhalation counts and durations

8. Histograms of inhalations over exhalations ratios

9. Histogram of total Apnea episodes

10. Histogram of total stimuli applied

11. Histogram of Apneas per hour

12. Histogram of Stimuli per hour

13. Histogram of Stimuli per Apnea

14. Standard Deviations for all calculated statistics

15. Detailed time stamped event logs for each apnea episode

Closed Loop Neuromodulator

Each of the closed loop neuromodulator's 4 internal building blockoutput signals are made available via individual signal output ports forconnection to a PSG for further analysis: These building blocks includethe digital signal 12 generated by the EMI/ESD hardened sensor Interface10, activity signal 22 generated by the Activity Detector 20, power-downsignal 24 generated by the Activity Detector 20, reset signal 26generated by the Activity Detector, start signal 32 generated by thestimulus timer, trigger signal 34 generated by the stimulus timer,driver signal 42 generated by the stimulus escalator, transducer output5 generated by the EMI/ESD hardened transducer driver, stimuli selectsignal 62 generated by the stimulus sequencer, stimuli signal 66generated by the stimulus sequencer, and stimuli output signal 72generated by the stimulus generator.

FIG. 3 is an electrical block diagram of one specific embodiment of theclosed loop neuromodulator 4 depicted in FIG. 2 and FIG. 1. There isindicated generally by numeral 4 a block diagram of the closed loopneuromodulator along with a sensor 2 and a transducer 6. Attached to thesensor and closed loop neuromodulator is a pair of wire terminations 3via which the closed loop neuromodulator receives the sensor output.Attached to the transducer and closed loop neuromodulator is a pair ofwire terminations 5 via which the closed loop neuromodulator transmitsthe transducer input. Furthermore the closed loop neuromodulatorindicated generally by numeral 4 contains a mixed signal microcontroller (such as a Freescale FireWire processor) or an FPGA basedprocessor (such as a National Instrument, LabVIEW based RIO virtualdevice development system) with internal processor, read-only memory(ROM), random access memory (RAM), reset manager, power pump,oscillator, analog-to-digital converter (ADC), digital-to-analogconverter (DAC) and embedded code.

The present invention is advantageous because it is directed towardprecise dosing of specific stimuli, which makes the device universallyeffective for most sleep patients. This is in contrast to the continuouspositive air pressure (CPAP), Bi-level positive air pressure (BPAP), andany other CNS Stimulation controller that arouses or wakes the patientof the prior art.

An additional advantage of the present invention is the precision withwhich stimulating doses can be given to a person suffering from variouskinds of neurological or sleeps disorders.

Another advantage of the present invention relates to the various typesof stimuli it can apply in order to avoid patient habituation.

An additional advantage is the device's ability to be used in aclinical, research or laboratory setting in order to diagnose patientsand figure out which type of stimuli works optimally for a specificpatient, a group of patients or any other setting.

An additional advantage is that upon detection of a no breathing signal,the device sends single stimuli of a certain level, frequency,modulation, and shape for certain duration to the patient. If breathingdoes not resume after a preset amount of time, then another yet strongerstimuli signal will be issued to the patient.

Another advantage is that the sequence of issuing stimuli and sendingthem to the patient continues until the resumption of breathing has beendetected.

Another advantage is that during low power operation functional blocksmay be shut down when not needed for immediate operation. E.g. shut downgenerators, timers and gain block when breathing is detected. Activategenerators, timers and gain block when no breathing is detected.

This further supports the device's ability to interrupt an undesirablebehavior while avoiding alteration of a sleep state.

This invention has been described herein in considerable detail in orderto comply with the patent statutes and to provide those skilled in theart with the information needed to apply the novel principles and toconstruct and use such specialized components as are required. However,it is to be understood that the invention can be carried out byspecifically different equipment and devices, and that variousmodifications, both as to the equipment and operating procedures, can beaccomplished without departing from the scope of the invention itself

The description of the various embodiments is merely exemplary in natureand, thus, variations that do not depart from the gist of the examplesand detailed description herein are intended to be within the scope ofthe present disclosure. Such variations are not to be regarded as adeparture from the spirit and scope of the present disclosure.

FIGS. 18A through 18C depict an embodiment of a sleep therapy device,which formed the basis of a feasibility study and is a device that wasused during clinical tests.

Below is a Bill-of-Materials of components for the components depictedin FIGS. 18A through 18C.

Reference Designator Value B1 9 V C1 10 uF/Tant C10 0.01 uF C11 0.039 uFC12 10 uF/Tant C13 0.39 uF C14 1 uF C15 0.1 uF C16 100 pF C17 1 uF C190.039 uF C2 10 uF/Tant C20 0.1 uF C21 1 uF C3 10 uF/Tant C4 0.1 uF C50.1 uF C7 0.39 uF C8 0.056 uF C9 10 uF/Tant D1 Green D2 5.6 V D3 RED D41N4148 D5 1N4148 J1 Header, 3-pin, F J2 Header, 3-pin, M J3 Header,2-pin, M J4 Header, 6-pin, M J5 Header, 6-pin, M R1   1M R10 560 k R11560 k R12 560 k R13 1 k R14 1.5 k R15 1 k R16 100 R17   10M R18  5.6MR19  2.7M R2 100 R20 100 k R21 1.35M R22 560 k R23 1 k R24 270 k R25  1M R28   1M R29 10 k R3 560 k R30   1M R31 220 k R32 20 k R33   1M R341 k R35   1M R36  2.2M R4 220 k R40 10 k R41 2.2 k R43 10 k R45 22 k R4722 k R48 10 R49 10 k R5 56 k R50 100 k R51 100 k R52 10 k R53 100 k R54330 k R55 220 k R56 150 k R57 82 k R58 47 k R6 5.6 k R7 27 k R8 100 k S1ON/OFF S2 6 pos Rotary Switch S3 6 pos Rotary Switch S4 6 pos RotarySwitch U1 TLE2426 U10: A CD4001 U10: B CD4001 U10: C CD4001 U10: DCD4001 U11: A CD4001 U11: B CD4001 U11: C CD4001 U11: D CD4001 U12: ACD4066 U12: B CD4066 U12: C CD4066 U12: D CD4066 U2: A LMC6482 U2: BLMC6482 U3: A CD4098 U3: B CD4098 U4: A LMC6482 U4: B LMC6482 U5: ACD4001 U5: B CD4001 U5: C CD4001 U5: D CD4001 U6 CD4060 U7: A LMC6482U7: B LMC6482 U8 CD4017 U9 CD4017

Additional Notes

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown and described. However, the present inventor alsocontemplates examples in which only those elements shown and describedare provided.

All publications, patents, and patent documents referred to in thisdocument are incorporated by reference herein in their entirety, asthough individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The above description is intended to be, and not restrictive. Forexample, the above-described examples (or one or more aspects thereof)may be used in combination with each other. Other embodiments can beused, such as by one of ordinary skill in the art upon reviewing theabove description. The Abstract is provided to comply with 37 C.F.R.§1.72(b), to allow the reader to quickly ascertain the nature of thetechnical disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims. Also, in the above Detailed Description, various features may begrouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, inventive subject matter may lie in lessthan all features of a particular disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment. The scopeof the invention should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

What is claimed is:
 1. A stimulus sequencer for generating a sleeptherapy stimulus waveform for a patient, the stimulus sequencercomprising: a sequence address generator configured to receive astimulus start signal from a timer of a closed loop neuromodulator andto provide an address related to a stimulus sequence of the sleeptherapy; a sequence memory array coupled to the sequence addressgenerator, the sequence memory array configured to select stimulussequence information related to the address; a stimulus generatorselector coupled to the sequence memory array, the stimulus generatorselector configured to receive the stimulus sequence information fromthe sequence memory array, to receive a stimulus duration signal fromthe timer of the closed loop neuromodulator, and to provide a generatorselect signal to a stimulus generator of the closed loop neuromodulatorusing the stimulus sequence information and the stimulus durationsignal, the generator select signal including stimulus type informationrelated to stimulus pulses generated using the closed loopneuromodulator; and wherein the sleep therapy stimulus waveform includesa sequence of one or more stimulus types.